diff --git a/pkg/nuclide-rust/lib/BuckIntegration.js b/pkg/nuclide-rust/lib/BuckIntegration.js
new file mode 100644
index 0000000000..ff15611790
--- /dev/null
+++ b/pkg/nuclide-rust/lib/BuckIntegration.js
@@ -0,0 +1,141 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the LICENSE file in
+ * the root directory of this source tree.
+ *
+ * @flow
+ * @format
+ */
+
+import type {BusySignalService, BusySignalOptions} from 'atom-ide-ui';
+import type {TaskInfo} from '../../nuclide-buck/lib/types';
+import type {
+  AtomLanguageService,
+  LanguageService,
+} from '../../nuclide-language-service';
+
+import {getLogger} from 'log4js';
+import fsPromise from 'nuclide-commons/fsPromise';
+import {
+  getRustBuildFile,
+  getRustInputs,
+  getSaveAnalysisTargets,
+  isRustBuildRuleType,
+  normalizeNameForBuckQuery,
+} from './BuckUtils';
+
+import * as BuckService from '../../nuclide-buck-rpc';
+
+const logger = getLogger('nuclide-rust');
+
+export async function updateRlsBuildForTask(
+  task: TaskInfo,
+  service: AtomLanguageService<LanguageService>,
+  busySignalService: ?BusySignalService,
+) {
+  if (!isRustBuildRuleType(task.buildRuleType.type)) {
+    return;
+  }
+  const buildTarget = normalizeNameForBuckQuery(task.buildTarget);
+
+  // Output is relative to Buck root but the built target may be managed by a
+  // Buck cell (nested Buck root).
+  // Here, Buck returns input paths relative to the possible cell, but the build
+  // file always relative to the current Buck root. Because of that, we use the
+  // build file path to determine the possible Buck cell root to which the
+  // inputs are relative to.
+  // FIXME: This is a bug in Buck, only query for files when the output is fixed.
+  const [relativeBuildFile, files] = await Promise.all([
+    getRustBuildFile(task.buckRoot, buildTarget),
+    getRustInputs(task.buckRoot, buildTarget),
+  ]);
+  // Not a Rust build target, ignore
+  if (relativeBuildFile == null || files.length === 0) {
+    return;
+  }
+
+  const buildFile = `${task.buckRoot}/${relativeBuildFile}`;
+  const buckRoot = await BuckService.getRootForPath(buildFile);
+  if (buckRoot == null) {
+    logger.error(`Couldn't find Buck root for ${buildFile}`);
+    return;
+  }
+
+  logger.debug(`Detected Buck root: ${buckRoot}`);
+  // We need only to pick a representative file to get a related lang service
+  const fileUri = buckRoot + '/' + files[0];
+
+  const langService = await service.getLanguageServiceForUri(fileUri);
+  if (langService == null) {
+    atom.notifications.addError(`[nuclide-rust] couldn't find language service
+      for target ${buildTarget}`);
+    return;
+  }
+
+  // Since `buck` execution is not trivial - the command may be overriden, needs
+  // to inherit the environment, passes internal FB USER to env etc. the RLS
+  // can't just invoke that.
+  // Instead, we build now, copy paths to resulting .json analysis artifacts to
+  // a temp file and just use `cat $TMPFILE` as a dummy build command.
+  const doSaveAnalysisBuild = () =>
+    getSaveAnalysisTargets(task.buckRoot, buildTarget).then(analysisTargets => {
+      logger.debug(`analysisTargets: ${analysisTargets.join('\n')}`);
+
+      return BuckService.build(task.buckRoot, analysisTargets);
+    });
+
+  const buildReport = await reportBusyWhile(
+    busySignalService,
+    '[nuclide-rust] Indexing...',
+    doSaveAnalysisBuild,
+  );
+
+  if (!buildReport.success) {
+    atom.notifications.addError('[nuclide-rust] save-analysis build failed');
+    return;
+  }
+
+  const artifacts: Array<string> = [];
+  Object.values(buildReport.results)
+    // TODO: https://buckbuild.com/command/build.html specifies that for
+    // FETCHED_FROM_CACHE we might not get an output file - can we force it
+    // somehow? Or we always locally produce a save-analysis .json file for
+    // #save-analysis flavor?
+    .forEach((targetReport: any) =>
+      artifacts.push(`${buckRoot}/${targetReport.output}`),
+    );
+
+  const tempfile = await fsPromise.tempfile();
+  await fsPromise.writeFile(tempfile, artifacts.join('\n'));
+
+  // TODO: Windows?
+  const buildCommand = `cat ${tempfile}`;
+
+  logger.debug(`Built SA artifacts: ${artifacts.join('\n')}`);
+  logger.debug(`buildCommand: ${buildCommand}`);
+
+  await langService.sendLspNotification('workspace/didChangeConfiguration', {
+    settings: {
+      rust: {
+        unstable_features: true, // Required for build_command
+        build_on_save: true,
+        build_command: buildCommand,
+      },
+    },
+  });
+}
+
+function reportBusyWhile<T>(
+  busySignalService: ?BusySignalService,
+  title: string,
+  f: () => Promise<T>,
+  options?: BusySignalOptions,
+): Promise<T> {
+  if (busySignalService) {
+    return busySignalService.reportBusyWhile(title, f, options);
+  } else {
+    return f();
+  }
+}
diff --git a/pkg/nuclide-rust/lib/BuckUtils.js b/pkg/nuclide-rust/lib/BuckUtils.js
new file mode 100644
index 0000000000..39e51915e9
--- /dev/null
+++ b/pkg/nuclide-rust/lib/BuckUtils.js
@@ -0,0 +1,71 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the LICENSE file in
+ * the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ */
+
+import * as BuckService from '../../nuclide-buck-rpc';
+
+export type BuildTarget = string;
+
+export function isRustBuildRuleType(type_: string): boolean {
+  return type_.startsWith('rust_');
+}
+
+export async function getRustBuildFile(
+  buckRoot: string,
+  buildTarget: BuildTarget,
+): Promise<?string> {
+  return BuckService.query(
+    buckRoot,
+    `buildfile(kind('^rust_.*', ${buildTarget}))`,
+    [],
+  ).then(buildfiles => buildfiles[0] || null);
+}
+
+export function getRustInputs(
+  buckRoot: string,
+  buildTarget: BuildTarget,
+): Promise<Array<string>> {
+  return BuckService.query(
+    buckRoot,
+    `filter('.*\\.rs$', inputs(kind('^rust_.*', ${buildTarget})))`,
+    [],
+  );
+}
+
+export async function getSaveAnalysisTargets(
+  buckRoot: string,
+  buildTarget: BuildTarget,
+): Promise<Array<string>> {
+  // Save-analysis build flavor is only supported by rust_{binary, library}
+  // kinds (so exclude prebuilt_rust_library kind)
+  const query: string = `kind('^rust_.*', deps(${buildTarget}))`;
+
+  const deps = await BuckService.query(buckRoot, query, []);
+  return deps.map(dep => dep + '#save-analysis');
+}
+
+// FIXME: Copied from nuclide-buck-rpc
+// Buck query doesn't allow omitting // or adding # for flavors, this needs to be fixed in buck.
+export function normalizeNameForBuckQuery(aliasOrTarget: string): BuildTarget {
+  let canonicalName = aliasOrTarget;
+  // Don't prepend // for aliases (aliases will not have colons or .)
+  if (
+    (canonicalName.indexOf(':') !== -1 || canonicalName.indexOf('.') !== -1) &&
+    canonicalName.indexOf('//') === -1
+  ) {
+    canonicalName = '//' + canonicalName;
+  }
+  // Strip flavor string
+  const flavorIndex = canonicalName.indexOf('#');
+  if (flavorIndex !== -1) {
+    canonicalName = canonicalName.substr(0, flavorIndex);
+  }
+  return canonicalName;
+}
diff --git a/pkg/nuclide-rust/lib/RustLanguage.js b/pkg/nuclide-rust/lib/RustLanguage.js
new file mode 100644
index 0000000000..670f1c2b57
--- /dev/null
+++ b/pkg/nuclide-rust/lib/RustLanguage.js
@@ -0,0 +1,124 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the LICENSE file in
+ * the root directory of this source tree.
+ *
+ * @flow
+ * @format
+ */
+
+import type {ServerConnection} from '../../nuclide-remote-connection';
+import type {AtomLanguageServiceConfig} from '../../nuclide-language-service/lib/AtomLanguageService';
+import type {LanguageService} from '../../nuclide-language-service/lib/LanguageService';
+
+import featureConfig from 'nuclide-commons-atom/feature-config';
+import {
+  AtomLanguageService,
+  getHostServices,
+} from '../../nuclide-language-service';
+import {NullLanguageService} from '../../nuclide-language-service-rpc';
+import {getNotifierByConnection} from '../../nuclide-open-files';
+import {getVSCodeLanguageServiceByConnection} from '../../nuclide-remote-connection';
+
+export function getRlsPath(): string {
+  return (featureConfig.get('nuclide-rust.rlsPath'): any);
+}
+
+async function connectionToRustService(
+  connection: ?ServerConnection,
+): Promise<LanguageService> {
+  const [fileNotifier, host] = await Promise.all([
+    getNotifierByConnection(connection),
+    getHostServices(),
+  ]);
+  const service = getVSCodeLanguageServiceByConnection(connection);
+
+  const lspService = await service.createMultiLspLanguageService(
+    'rust',
+    getRlsPath(),
+    [],
+    {
+      fileNotifier,
+      host,
+      projectFileNames: ['Cargo.toml', '.buckconfig'],
+      fileExtensions: ['.rs'],
+      logCategory: 'nuclide-rust',
+      logLevel: 'TRACE',
+      useOriginalEnvironment: true,
+      additionalLogFilesRetentionPeriod: 5 * 60 * 1000, // 5 minutes
+      waitForDiagnostics: true,
+      initializationOptions: {
+        // Don't let RLS eagerly build (and fail crashing while finding a
+        // Cargo.toml if the project uses Buck) for now.
+        // TODO: Pass initial config (at least the `build_command`).
+        // https://github.com/rust-lang-nursery/rls/issues/1026
+        // Without this the RLS can still can crash when the user starts
+        // modifying .rs files.
+        omitInitBuild: true,
+      },
+    },
+  );
+
+  return lspService || new NullLanguageService();
+}
+
+export const atomConfig: AtomLanguageServiceConfig = {
+  name: 'Rust',
+  grammars: ['source.rust'],
+  diagnostics: {
+    version: '0.2.0',
+    analyticsEventName: 'rust.observe-diagnostics',
+  },
+  definition: {
+    version: '0.1.0',
+    priority: 1,
+    definitionEventName: 'rust.definition',
+  },
+  codeAction: {
+    version: '0.1.0',
+    priority: 1,
+    analyticsEventName: 'rust.codeAction',
+    applyAnalyticsEventName: 'rust.applyCodeAction',
+  },
+  codeFormat: {
+    version: '0.1.0',
+    priority: 1,
+    analyticsEventName: 'rust.codeFormat',
+    canFormatRanges: true,
+    canFormatAtPosition: true,
+  },
+  findReferences: {
+    version: '0.1.0',
+    analyticsEventName: 'rust.findReferences',
+  },
+  rename: {
+    version: '0.0.0',
+    priority: 1,
+    analyticsEventName: 'rust.rename',
+  },
+  autocomplete: {
+    inclusionPriority: 1,
+    suggestionPriority: 3,
+    excludeLowerPriority: false,
+    analytics: {
+      eventName: 'nuclide-rust',
+      shouldLogInsertedSuggestion: false,
+    },
+    disableForSelector: '.source.rust .comment, .source.rust .string',
+    autocompleteCacherConfig: null,
+    supportsResolve: false,
+  },
+  typeHint: {
+    version: '0.0.0',
+    priority: 1,
+    analyticsEventName: 'rust.typeHint',
+  },
+};
+
+export function createRustLanguageService(): AtomLanguageService<
+  LanguageService,
+> {
+  return new AtomLanguageService(connectionToRustService, atomConfig);
+}
diff --git a/pkg/nuclide-rust/lib/main.js b/pkg/nuclide-rust/lib/main.js
new file mode 100644
index 0000000000..4719e2cdd1
--- /dev/null
+++ b/pkg/nuclide-rust/lib/main.js
@@ -0,0 +1,65 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the LICENSE file in
+ * the root directory of this source tree.
+ *
+ * @flow
+ * @format
+ */
+
+import type {BuckTaskRunnerService} from '../../nuclide-buck/lib/types';
+import type {BusySignalService} from 'atom-ide-ui';
+import type {
+  AtomLanguageService,
+  LanguageService,
+} from '../../nuclide-language-service';
+
+import createPackage from 'nuclide-commons-atom/createPackage';
+import UniversalDisposable from 'nuclide-commons/UniversalDisposable';
+import {createRustLanguageService} from './RustLanguage';
+
+import {updateRlsBuildForTask} from './BuckIntegration';
+
+const DISCLAIMER = `[nuclide-rust] Support for Buck-managed Rust
+projects is currently experimental. For it to work correctly, please build
+the target you plan on working using Buck toolbar.`;
+
+class Activation {
+  _rustLanguageService: AtomLanguageService<LanguageService>;
+  _subscriptions: UniversalDisposable;
+  _busySignalService: ?BusySignalService;
+
+  constructor(rawState: ?Object) {
+    atom.notifications.addInfo(DISCLAIMER);
+
+    this._rustLanguageService = createRustLanguageService();
+    this._rustLanguageService.activate();
+
+    this._subscriptions = new UniversalDisposable(this._rustLanguageService);
+  }
+
+  consumeBuckTaskRunner(service: BuckTaskRunnerService): IDisposable {
+    return service.onDidCompleteTask(task =>
+      updateRlsBuildForTask(
+        task,
+        this._rustLanguageService,
+        this._busySignalService,
+      ),
+    );
+  }
+
+  consumeBusySignal(busySignalService: BusySignalService): IDisposable {
+    this._busySignalService = busySignalService;
+    return new UniversalDisposable(() => {
+      this._busySignalService = null;
+    });
+  }
+
+  dispose(): void {
+    this._subscriptions.dispose();
+  }
+}
+
+createPackage(module.exports, Activation);
diff --git a/pkg/nuclide-rust/package.json b/pkg/nuclide-rust/package.json
new file mode 100644
index 0000000000..cafd505452
--- /dev/null
+++ b/pkg/nuclide-rust/package.json
@@ -0,0 +1,40 @@
+{
+  "name": "nuclide-rust",
+  "main": "./lib/main.js",
+  "version": "0.0.0",
+  "description": "Provides Rust language support in Nuclide",
+  "author": "NEEDS OWNER",
+  "atomTestRunner": "../../lib/test-runner-entry.js",
+  "nuclide": {
+    "packageType": "AtomPackage",
+    "configMetadata": {
+      "pathComponents": [
+        "Language",
+        "Rust"
+      ]
+    },
+    "config": {
+      "rlsPath": {
+        "title": "Rust Language Server path",
+        "type": "string",
+        "default": "rls",
+        "description": "Path to the RLS executable. By default uses rustup-managed 'rls' executable."
+      }
+    }
+  },
+  "activationHooks": [
+    "language-rust:grammar-used"
+  ],
+  "consumedServices": {
+    "atom-ide-busy-signal": {
+      "versions": {
+        "0.1.0": "consumeBusySignal"
+      }
+    },
+    "nuclide.buck-task-runner": {
+      "versions": {
+        "0.0.0": "consumeBuckTaskRunner"
+      }
+    }
+  }
+}