diff --git a/ipynb/Palindrome.ipynb b/ipynb/Palindrome.ipynb
index 985ca0be..44b7f9f6 100644
--- a/ipynb/Palindrome.ipynb
+++ b/ipynb/Palindrome.ipynb
@@ -214,7 +214,7 @@
     "        self.seen = {}\n",
     "        self.diff = 0\n",
     "        self.stack = []\n",
-    "        self.starttime = time.clock()\n",
+    "        self.starttime = time.process_time()\n",
     "        self.dict = dict\n",
     "        self.steps = 0\n",
     "        for word in L.split(','):\n",
@@ -286,7 +286,7 @@
     "            self.best = len(self)\n",
     "            self.bestphrase = str(self)\n",
     "            print('%5d phrases (%5d words) in %3d seconds (%6d steps)' % (\n",
-    "                self.best, self.bestphrase.count(' ')+1, time.clock() - self.starttime,\n",
+    "                self.best, self.bestphrase.count(' ')+1, time.process_time() - self.starttime,\n",
     "                self.steps))\n",
     "            assert is_unique_palindrome(self.bestphrase)\n",
     "\n",
diff --git a/ipynb/Sudoku IPython Notebook.ipynb b/ipynb/Sudoku IPython Notebook.ipynb
index 6ca53a9b..2154a291 100644
--- a/ipynb/Sudoku IPython Notebook.ipynb	
+++ b/ipynb/Sudoku IPython Notebook.ipynb	
@@ -516,9 +516,9 @@
     "def do1(puzzle):\n",
     "    \"Do one puzzle; showing puzzle and solution and printing elapsed time.\"\n",
     "    show(puzzle)\n",
-    "    t0 = time.clock()\n",
+    "    t0 = time.process_time()\n",
     "    solution = solve(Grid(puzzle))\n",
-    "    t1 = time.clock()\n",
+    "    t1 = time.process_time()\n",
     "    assert is_solution(solution, puzzle)\n",
     "    show(solution)\n",
     "    print('{:.3f} seconds'.format(t1 - t0))\n",
@@ -998,9 +998,9 @@
     "def benchmark(label, puzzles=puzzles):\n",
     "    \"Run `solve` on these puzzles; record and verify results for this label; print all results.\"\n",
     "    n = len(puzzles)\n",
-    "    t0 = time.clock()\n",
+    "    t0 = time.process_time()\n",
     "    results = [solve(Grid(p)) for p in puzzles]\n",
-    "    avg = (time.clock() - t0) / len(puzzles)\n",
+    "    avg = (time.process_time() - t0) / len(puzzles)\n",
     "    for (r, p) in zip(results, puzzles):\n",
     "        assert is_solution(r, p) \n",
     "    benchmarks[label] = '{:.3f} sec/puzzle ({:.1f} Hz)'.format(avg, 1/avg)\n",
diff --git a/py/pal2.py b/py/pal2.py
index 4faecb4f..f48b3ace 100644
--- a/py/pal2.py
+++ b/py/pal2.py
@@ -127,7 +127,7 @@ def __init__(self, L='A man, a plan', R='a canal, Panama', dict=paldict):
         ##  positive for words on left, negative for right.
         ## .stack holds (action, side, arg) tuples
         update(self, left=[], right=[], best=0, seen={}, diff=0, stack=[],
-               used_reversibles=False, starttime=time.clock(), dict=dict)
+               used_reversibles=False, starttime=time.process_time(), dict=dict)
         for word in L.split(','):
             self.add('left', canonical(word))
         for rword in reversestr(R).split(','):
@@ -209,7 +209,7 @@ def report(self):
             self.best = len(self)
             self.bestphrase = str(self)
             print('%5d phrases (%5d words) in %3d seconds' % (
-                self.best, self.bestphrase.count(' ')+1, time.clock() - self.starttime))
+                self.best, self.bestphrase.count(' ')+1, time.process_time() - self.starttime))
             assert is_panama(self.bestphrase)
             f = open('pallog%d.txt' % (id(self) % 10000), 'w')
             f.write(self.bestphrase + '\n')
diff --git a/py/spell.py b/py/spell.py
index ac37b9b9..6720301b 100644
--- a/py/spell.py
+++ b/py/spell.py
@@ -79,7 +79,7 @@ def unit_tests():
 def spelltest(tests, verbose=False):
     "Run correction(wrong) on all (right, wrong) pairs; report results."
     import time
-    start = time.clock()
+    start = time.process_time()
     good, unknown = 0, 0
     n = len(tests)
     for right, wrong in tests:
@@ -90,7 +90,7 @@ def spelltest(tests, verbose=False):
             if verbose:
                 print('correction({}) => {} ({}); expected {} ({})'
                       .format(wrong, w, WORDS[w], right, WORDS[right]))
-    dt = time.clock() - start
+    dt = time.process_time() - start
     print('{:.0%} of {} correct ({:.0%} unknown) at {:.0f} words per second '
           .format(good / n, n, unknown / n, n / dt))
     
diff --git a/py/sudoku.py b/py/sudoku.py
index db8b81e3..2b887647 100644
--- a/py/sudoku.py
+++ b/py/sudoku.py
@@ -138,9 +138,9 @@ def solve_all(grids, name=''):
             sum(results), N, name, sum(times)/N, N/sum(times), max(times)))
             
 def time_solve(grid):
-    start = time.clock()
+    start = time.process_time()
     values = solve(grid)
-    t = time.clock()-start
+    t = time.process_time()-start
     return (t, solved(values))
 
 def solved(values):