diff --git a/README.md b/README.md
old mode 100644
new mode 100755
index 9c2113d2..dce07abc
--- a/README.md
+++ b/README.md
@@ -91,6 +91,7 @@ See the [wiki](https://github.com/fogleman/Minecraft/wiki) for this project to i
 - Mouse: look around
 - Space: jump
 - Tab: toggle flying mode
+- Left Shift: run
 
 ### Building
 
diff --git a/main.py b/main.py
old mode 100644
new mode 100755
index 84fc069d..9916a19a
--- a/main.py
+++ b/main.py
@@ -16,7 +16,8 @@
 # Size of sectors used to ease block loading.
 SECTOR_SIZE = 16
 
-WALKING_SPEED = 5
+WALKING_SPEED = 2
+RUNNING_SPEED = 5
 FLYING_SPEED = 15
 
 GRAVITY = 20.0
@@ -442,6 +443,9 @@ def __init__(self, *args, **kwargs):
         # When flying gravity has no effect and speed is increased.
         self.flying = False
 
+        # Determine if player is running. If false, then player is walking.
+        self.running = False
+
         # Strafing is moving lateral to the direction you are facing,
         # e.g. moving to the left or right while continuing to face forward.
         #
@@ -591,7 +595,7 @@ def _update(self, dt):
 
         """
         # walking
-        speed = FLYING_SPEED if self.flying else WALKING_SPEED
+        speed = FLYING_SPEED if self.flying else RUNNING_SPEED if self.running else WALKING_SPEED
         d = dt * speed # distance covered this tick.
         dx, dy, dz = self.get_motion_vector()
         # New position in space, before accounting for gravity.
@@ -733,6 +737,8 @@ def on_key_press(self, symbol, modifiers):
             self.set_exclusive_mouse(False)
         elif symbol == key.TAB:
             self.flying = not self.flying
+        elif symbol == key.LSHIFT:
+            self.running = True
         elif symbol in self.num_keys:
             index = (symbol - self.num_keys[0]) % len(self.inventory)
             self.block = self.inventory[index]
@@ -757,6 +763,8 @@ def on_key_release(self, symbol, modifiers):
             self.strafe[1] += 1
         elif symbol == key.D:
             self.strafe[1] -= 1
+        elif symbol == key.LSHIFT:
+            self.running = False
 
     def on_resize(self, width, height):
         """ Called when the window is resized to a new `width` and `height`.