diff -r d0ed9643cd57 Lib/subprocess.py
--- a/Lib/subprocess.py	Thu Nov 17 23:31:29 2016 -0600
+++ b/Lib/subprocess.py	Sat Nov 19 22:19:53 2016 -0800
@@ -1031,6 +1031,10 @@
             """Wait for child process to terminate.  Returns returncode
             attribute."""
             if endtime is not None:
+                warnings.warn(
+                    "'endtime' argument is deprecated. Use 'timeout' instead",
+                    DeprecationWarning,
+                    stacklevel=2)
                 timeout = self._remaining_time(endtime)
             if timeout is None:
                 timeout_millis = _winapi.INFINITE
@@ -1392,9 +1396,13 @@
             if self.returncode is not None:
                 return self.returncode
 
-            # endtime is preferred to timeout.  timeout is only used for
-            # printing.
             if endtime is not None or timeout is not None:
+                if endtime is not None:
+                    warnings.warn(
+                        "'endtime' argument is deprecated. "
+                        "Use 'timeout' instead",
+                        DeprecationWarning,
+                        stacklevel=2)
                 if endtime is None:
                     endtime = _time() + timeout
                 elif timeout is None:
diff -r d0ed9643cd57 Lib/test/test_subprocess.py
--- a/Lib/test/test_subprocess.py	Thu Nov 17 23:31:29 2016 -0600
+++ b/Lib/test/test_subprocess.py	Sat Nov 19 22:19:53 2016 -0800
@@ -1015,6 +1015,13 @@
         # time to start.
         self.assertEqual(p.wait(timeout=3), 0)
 
+    def test_wait_endtime(self):
+        p = subprocess.Popen([sys.executable, "-c", "pass"])
+        with self.assertRaises(subprocess.TimeoutExpired), \
+                self.assertWarns(DeprecationWarning):
+            result = p.wait(endtime=0.0001)
+            self.assertEqual(result, 0)
+
     def test_invalid_bufsize(self):
         # an invalid type of the bufsize argument should raise
         # TypeError.