diff --git a/pyflakes/checker.py b/pyflakes/checker.py
index bd5eba5..a41980e 100644
--- a/pyflakes/checker.py
+++ b/pyflakes/checker.py
@@ -1235,6 +1235,8 @@ class Checker(object):
                 Check to see if any assignments have not been used.
                 """
                 for name, binding in self.scope.unusedAssignments():
+                    if name == "_":
+                        continue
                     self.report(messages.UnusedVariable, binding.source, name)
             self.deferAssignment(checkUnusedAssignments)
 
@@ -1414,7 +1416,7 @@ class Checker(object):
         except KeyError:
             pass
         else:
-            if not binding.used:
+            if not binding.used and node.name != "_":
                 self.report(messages.UnusedVariable, node, node.name)
 
         # Restore.