diff --git a/go.mod b/go.mod
index b709d7f..8d787e7 100644
--- a/go.mod
+++ b/go.mod
@@ -4,4 +4,4 @@ require (
 	github.com/stretchr/testify v1.3.0
 	github.com/xeipuuv/gojsonpointer v0.0.0-20180127040702-4e3ac2762d5f // indirect
 	github.com/xeipuuv/gojsonreference v0.0.0-20180127040603-bd5ef7bd5415
-)
+)
\ No newline at end of file
diff --git a/validation.go b/validation.go
index 9081bd9..c46335c 100644
--- a/validation.go
+++ b/validation.go
@@ -27,6 +27,7 @@ package gojsonschema
 
 import (
 	"encoding/json"
+	"errors"
 	"math/big"
 	"reflect"
 	"regexp"
@@ -42,9 +43,22 @@ func Validate(ls JSONLoader, ld JSONLoader) (*Result, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	if err := schema.ValidateSchema(); err != nil {
+		return nil, err
+	}
+
 	return schema.Validate(ld)
 }
 
+func (v *Schema) ValidateSchema() error {
+	if v.rootSchema == nil || v.rootSchema.types.types == nil {
+		return errors.New("type is missing in root")
+	}
+
+	return nil
+}
+
 // Validate loads and validates a JSON document
 func (v *Schema) Validate(l JSONLoader) (*Result, error) {
 	root, err := l.LoadJSON()