diff --git a/Lib/re.py b/Lib/re.py
index 9bd913a68dd..2f1a76eaa52 100644
--- a/Lib/re.py
+++ b/Lib/re.py
@@ -254,7 +254,40 @@ _cache_repl = {}
 
 _pattern_type = type(sre_compile.compile("", 0))
 
-_MAXCACHE = 100
+_MAXCACHE = 500
+
+def _shrink_cache(cache_dict, max_length, divisor=5):
+    """Make room in the given cache.
+
+    Args:
+        cache_dict: The cache dictionary to modify.
+        max_length: Maximum # of entries in cache_dict before it is shrunk.
+        divisor: Cache will shrink to max_length - 1/divisor*max_length items.
+    """
+    # Toss out a fraction of the entries at random to make room for new ones.
+    # A random algorithm was chosen as opposed to simply cache_dict.popitem()
+    # as popitem could penalize the same regular expression repeatedly based
+    # on its internal hash value.  Being random should spread the cache miss
+    # love around.
+    cache_keys = tuple(cache_dict.keys())
+    overage = len(cache_keys) - max_length
+    if overage < 0:
+        # Cache is already within limits.  Normally this should not happen
+        # but it could due to multithreading.
+        return
+    number_to_toss = max_length // divisor + overage
+    # The import is done here to avoid a circular depencency.
+    import random
+    if not hasattr(random, 'sample'):
+        # Do nothing while resolving the circular dependency:
+        #  re->random->warnings->tokenize->string->re
+        return
+    for doomed_key in random.sample(cache_keys, number_to_toss):
+        try:
+            del cache_dict[doomed_key]
+        except KeyError:
+            # Ignore problems if the cache changed from another thread.
+            pass
 
 def _compile(*key):
     # internal: compile pattern
@@ -272,7 +305,7 @@ def _compile(*key):
         raise TypeError("first argument must be string or compiled pattern")
     p = sre_compile.compile(pattern, flags)
     if len(_cache) >= _MAXCACHE:
-        _cache.clear()
+        _shrink_cache(_cache, _MAXCACHE)
     _cache[cachekey] = p
     return p
 
@@ -284,7 +317,7 @@ def _compile_repl(*key):
     repl, pattern = key
     p = sre_parse.parse_template(repl, pattern)
     if len(_cache_repl) >= _MAXCACHE:
-        _cache_repl.clear()
+        _shrink_cache(_cache_repl, _MAXCACHE)
     _cache_repl[key] = p
     return p
 
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index 7b0a8dd419c..6b11685e9c8 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -874,8 +874,71 @@ def run_re_tests():
                 if result is None:
                     print('=== Fails on unicode-sensitive match', t)
 
+
+class ReCacheTests(unittest.TestCase):
+    """These tests are specific to the re._shrink_cache implementation."""
+
+    def setUp(self):
+        self._orig_maxcache = re._MAXCACHE
+
+    def tearDown(self):
+        re._MAXCACHE = self._orig_maxcache
+
+    def test_compile_cache_overflow(self):
+        # NOTE: If a profiler or debugger is tracing code and compiling
+        # regular expressions while tracing through this test... expect
+        # the test to fail.  This test is not concurrency safe.
+
+        # Explicitly fill the caches.
+        re._MAXCACHE = 20
+        max_cache = re._MAXCACHE
+        unique_chars = tuple(chr(char_num) for char_num in
+                             range(b'a'[0], b'a'[0]+max_cache))
+        re._cache.clear()
+        for char in unique_chars:
+            re._compile(char, 0)
+        self.assertEqual(max_cache, len(re._cache))
+        re._cache_repl.clear()
+        for char in unique_chars:
+            re._compile_repl(char*2, char)
+        self.assertEqual(max_cache, len(re._cache_repl))
+
+        # Overflow both caches and make sure they have extra room left
+        # afterwards as well as having more than a single entry.
+        re._compile('A', 0)
+        self.assertLess(len(re._cache), max_cache)
+        self.assertGreater(len(re._cache), 1)
+        re._compile_repl('A', 'A')
+        self.assertLess(len(re._cache_repl), max_cache)
+        self.assertGreater(len(re._cache_repl), 1)
+
+    def test_shrink_cache_at_limit(self):
+        cache = dict(zip(range(6), range(6)))
+        re._shrink_cache(cache, 6, divisor=3)
+        self.assertEqual(4, len(cache))
+
+    def test_shrink_cache_empty(self):
+        cache = {}
+        re._shrink_cache(cache, 6, divisor=3)
+        # Cache was empty, make sure we didn't raise an exception.
+        self.assertEqual(0, len(cache))
+
+    def test_shrink_cache_overflowing(self):
+        cache = dict(zip(range(6), range(6)))
+        re._shrink_cache(cache, 4, divisor=2)
+        # Cache was larger than the maximum, be sure we shrunk to smaller.
+        self.assertEqual(2, len(cache))
+
+    def test_shrink_cache_underflow(self):
+        cache = dict(zip(range(6), range(6)))
+        # No shrinking to do.
+        re._shrink_cache(cache, 9, divisor=3)
+        self.assertEqual(6, len(cache))
+
+
 def test_main():
     run_unittest(ReTests)
+    run_unittest(ReCacheTests)
     run_re_tests()
 
 if __name__ == "__main__":
diff --git a/Misc/NEWS b/Misc/NEWS
index 70a646f65d9..a6a7c20f26a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -473,6 +473,13 @@ C-API
 Library
 -------
 
+- The default size of the re module's compiled regular expression cache has
+  been increased from 100 to 500 and the cache replacement policy has changed
+  from simply clearing the entire cache on overflow to randomly forgetting 20%
+  of the existing cached compiled regular expressions.  This is a performance
+  win for applications that use a lot of regular expressions and limits the
+  impact of the performance hit anytime the cache is exceeded.
+
 - Issue #7113: Speed up loading in configparser. Patch by Łukasz Langa.
 
 - Issue #9032: XML-RPC client retries the request on EPIPE error. The EPIPE