diff --git a/tests/modelling/test_engine.py b/tests/modelling/test_engine.py
index 41c1752d..cf67354e 100644
--- a/tests/modelling/test_engine.py
+++ b/tests/modelling/test_engine.py
@@ -85,6 +85,16 @@ class ConstantInputTestCase(TestCase):
         )
         self.asset_finder = AssetFinder(self.asset_info)
 
+    def test_bad_dates(self):
+        loader = self.loader
+        engine = SimpleFFCEngine(loader, self.dates, self.asset_finder)
+
+        msg = "start_date must be before end_date .*"
+        with self.assertRaisesRegexp(ValueError, msg):
+            engine.factor_matrix({}, self.dates[2], self.dates[1])
+        with self.assertRaisesRegexp(ValueError, msg):
+            engine.factor_matrix({}, self.dates[2], self.dates[2])
+
     def test_single_factor(self):
         loader = self.loader
         engine = SimpleFFCEngine(loader, self.dates, self.asset_finder)
diff --git a/zipline/modelling/engine.py b/zipline/modelling/engine.py
index 5814f67a..52ffd5bd 100644
--- a/zipline/modelling/engine.py
+++ b/zipline/modelling/engine.py
@@ -226,6 +226,12 @@ class SimpleFFCEngine(object):
         --------
         FFCEngine.factor_matrix
         """
+        if end_date <= start_date:
+            raise ValueError(
+                "start_date must be before end_date \n"
+                "start_date=%s, end_date=%s" % (start_date, end_date)
+            )
+
         graph = build_dependency_graph(terms.values())
         ordered_terms = topological_sort(graph)
         extra_row_counts = get_node_attributes(graph, 'extra_rows')