diff -r e9cecb612ff7 Lib/test/datetimetester.py
--- a/Lib/test/datetimetester.py	Sat Aug 03 21:19:10 2013 +0300
+++ b/Lib/test/datetimetester.py	Sat Aug 03 17:58:10 2013 -0400
@@ -619,6 +619,10 @@
         eq(td(hours=-.2/us_per_hour), td(0))
         eq(td(days=-.4/us_per_day, hours=-.2/us_per_hour), td(microseconds=-1))
 
+        # Test for a patch in Issue 8860
+        eq(td(microseconds=0.5), 0.5*td(microseconds=1.0))
+        eq(td(microseconds=0.5)//td.resolution, 0.5*td.resolution//td.resolution)
+
     def test_massive_normalization(self):
         td = timedelta(microseconds=-1)
         self.assertEqual((td.days, td.seconds, td.microseconds),
diff -r e9cecb612ff7 Modules/_datetimemodule.c
--- a/Modules/_datetimemodule.c	Sat Aug 03 21:19:10 2013 +0300
+++ b/Modules/_datetimemodule.c	Sat Aug 03 17:58:10 2013 -0400
@@ -140,19 +140,6 @@
     return quo;
 }
 
-/* Round a double to the nearest long.  |x| must be small enough to fit
- * in a C long; this is not checked.
- */
-static long
-round_to_long(double x)
-{
-    if (x >= 0.0)
-        x = floor(x + 0.5);
-    else
-        x = ceil(x - 0.5);
-    return (long)x;
-}
-
 /* Nearest integer to m / n for integers m and n. Half-integer results
  * are rounded to even.
  */
@@ -2148,7 +2135,30 @@
     }
     if (leftover_us) {
         /* Round to nearest whole # of us, and add into x. */
-        PyObject *temp = PyLong_FromLong(round_to_long(leftover_us));
+        double whole_us = round(leftover_us);
+        int x_is_odd;
+        PyObject *temp;
+
+        whole_us = round(leftover_us);
+        if (fabs(whole_us - leftover_us) == 0.5) {
+            /* We're exactly halfway between two integers.  In order to do
+             * round-half-to-even, we must determine whether x is odd. */
+            temp = PyNumber_And(x, us_per_us);
+            if (temp == NULL) {
+                Py_DECREF(x);
+                goto Done;
+            }
+            x_is_odd = PyObject_IsTrue(temp);
+            Py_DECREF(temp);
+            if (x_is_odd == -1) {
+                Py_DECREF(x);
+                goto Done;
+            }
+            whole_us = 2.0 * round((leftover_us + x_is_odd) * 0.5) - x_is_odd;
+        }
+
+        temp = PyLong_FromLong(whole_us);
+
         if (temp == NULL) {
             Py_DECREF(x);
             goto Done;