diff --git a/tests/test_algorithm.py b/tests/test_algorithm.py
index be953be2..76b3ddc0 100644
--- a/tests/test_algorithm.py
+++ b/tests/test_algorithm.py
@@ -25,6 +25,7 @@ from zipline.sources import (SpecificEquityTrades,
                              DataFrameSource,
                              DataPanelSource)
 from zipline.transforms import MovingAverage
+from zipline.finance.trading import SimulationParameters
 
 
 class TestRecordAlgorithm(TestCase):
@@ -88,12 +89,15 @@ class TestTransformAlgorithm(TestCase):
             algo.run([self.source, self.df_source])
 
     def test_multi_source_as_input(self):
+        sim_params = SimulationParameters(
+            self.df.index[0],
+            self.df.index[-1]
+        )
         algo = TestRegisterTransformAlgorithm(
-            self.sim_params,
+            sim_params=sim_params,
             sids=[0, 1, 133]
         )
-        algo.run([self.source, self.df_source],
-                 start=self.df.index[0], end=self.df.index[-1])
+        algo.run([self.source, self.df_source])
         self.assertEqual(len(algo.sources), 2)
 
     def test_df_as_input(self):
diff --git a/zipline/algorithm.py b/zipline/algorithm.py
index b4005946..4dd064a6 100644
--- a/zipline/algorithm.py
+++ b/zipline/algorithm.py
@@ -150,7 +150,7 @@ class TradingAlgorithm(object):
     # TODO: make a new subclass, e.g. BatchAlgorithm, and move
     # the run method to the subclass, and refactor to put the
     # generator creation logic into get_generator.
-    def run(self, source, start=None, end=None):
+    def run(self, source, sim_params=None):
         """Run the algorithm.
 
         :Arguments:
@@ -172,9 +172,10 @@ class TradingAlgorithm(object):
 
         """
         if isinstance(source, (list, tuple)):
-            assert start is not None and end is not None, \
+            assert self.sim_params is not None or sim_params is not None, \
                 """When providing a list of sources, \
-                start and end date have to be specified."""
+                sim_params have to be specified as a parameter
+                or in the constructor."""
         elif isinstance(source, pd.DataFrame):
             # if DataFrame provided, wrap in DataFrameSource
             source = DataFrameSource(source)
@@ -182,9 +183,8 @@ class TradingAlgorithm(object):
             source = DataPanelSource(source)
 
         # If values not set, try to extract from source.
-        if start is None:
+        if self.sim_params is None and sim_params is None:
             start = source.start
-        if end is None:
             end = source.end
 
         if not isinstance(source, (list, tuple)):
@@ -192,6 +192,9 @@ class TradingAlgorithm(object):
         else:
             self.sources = source
 
+        if sim_params:
+            self.sim_params = sim_params
+
         if not self.sim_params:
             self.sim_params = create_simulation_parameters(
                 start=start,