diff --git a/pyflakes/checker.py b/pyflakes/checker.py
index fe201462..bea2f56d 100644
--- a/pyflakes/checker.py
+++ b/pyflakes/checker.py
@@ -229,6 +229,14 @@ def __repr__(self):
         scope_cls = self.__class__.__name__
         return '<%s at 0x%x %s>' % (scope_cls, id(self), dict.__repr__(self))
 
+    def unusedAssignments(self):
+        """
+        Return a generator for the assignments which have not been used.
+        """
+        for name, binding in self.items():
+            if not binding.used and isinstance(binding, Assignment):
+                yield name, binding
+
 
 class ClassScope(Scope):
     pass
@@ -254,11 +262,15 @@ def __init__(self):
     def unusedAssignments(self):
         """
         Return a generator for the assignments which have not been used.
+
+        All assignments are considered used when a scope uses locals().
+
+        Unused names in alwaysUsed are skipped.
         """
-        for name, binding in self.items():
-            if (not binding.used and name not in self.globals
-                    and not self.usesLocals
-                    and isinstance(binding, Assignment)):
+        if self.usesLocals:
+            return
+        for name, binding in super(FunctionScope, self).unusedAssignments():
+            if name not in self.globals:
                 yield name, binding
 
 
@@ -274,6 +286,16 @@ class ModuleScope(Scope):
 class DoctestScope(ModuleScope):
     """Scope for a doctest."""
 
+    def unusedAssignments(self):
+        """
+        Return a generator for the assignments which have not been used.
+
+        '_' is never unused.
+        """
+        for name, binding in super(DoctestScope, self).unusedAssignments():
+            if name != '_':
+                yield name, binding
+
 
 # Globally defined names which are not attributes of the builtins module, or
 # are only present on some platforms.
@@ -390,6 +412,13 @@ def scope(self):
     def popScope(self):
         self.deadScopes.append(self.scopeStack.pop())
 
+    def _check_unused_assignments(self):
+        """
+        Check to see if any assignments have not been used.
+        """
+        for name, binding in self.scope.unusedAssignments():
+            self.report(messages.UnusedVariable, binding.source, name)
+
     def checkDeadScopes(self):
         """
         Look at scopes which have been fully examined and report names in them
@@ -738,6 +767,7 @@ def handleDoctests(self, node):
                 self.offset = node_offset
         if not underscore_in_builtins:
             self.builtIns.remove('_')
+        self.deferAssignment(self._check_unused_assignments)
         self.popScope()
         self.scopeStack = saved_stack
 
@@ -959,13 +989,7 @@ def runFunction():
                 # case for Lambdas
                 self.handleNode(node.body, node)
 
-            def checkUnusedAssignments():
-                """
-                Check to see if any assignments have not been used.
-                """
-                for name, binding in self.scope.unusedAssignments():
-                    self.report(messages.UnusedVariable, binding.source, name)
-            self.deferAssignment(checkUnusedAssignments)
+            self.deferAssignment(self._check_unused_assignments)
 
             if PY32:
                 def checkReturnWithArgumentInsideGenerator():
diff --git a/pyflakes/test/test_doctests.py b/pyflakes/test/test_doctests.py
index aed7957b..fcc53474 100644
--- a/pyflakes/test/test_doctests.py
+++ b/pyflakes/test/test_doctests.py
@@ -62,6 +62,8 @@ def test_scope_class(self):
         def doctest_stuff():
             '''
                 >>> d = doctest_stuff()
+                >>> d
+                None
             '''
             f = m
             return f
@@ -238,6 +240,24 @@ def doctest_stuff(self):
             m = 1
         """, m.UndefinedName)
 
+    def test_assignment_unused(self):
+        """Report unused assignments."""
+        self.flakes("""
+        def doctest_stuff():
+            '''
+                >>> foo = 1
+            '''
+        """, m.UnusedVariable)
+
+    def test_assignment_underscore(self):
+        """Assign to underscore (_) to avoid a doctest output."""
+        self.flakes("""
+        def doctest_stuff():
+            '''
+                >>> _ = 1
+            '''
+        """)
+
     def test_importBeforeDoctest(self):
         self.flakes("""
         import foo
@@ -304,12 +324,14 @@ def test_offsetAfterDoctests(self):
         def doctest_stuff():
             """
                 >>> x = 5
+                >>> x
+                5
             """
 
         x
 
         ''', m.UndefinedName).messages[0]
-        self.assertEqual(exc.lineno, 8)
+        self.assertEqual(exc.lineno, 10)
         self.assertEqual(exc.col, 0)
 
     def test_syntaxErrorInDoctest(self):
diff --git a/pyflakes/test/test_imports.py b/pyflakes/test/test_imports.py
index 21015795..fc341b9e 100644
--- a/pyflakes/test/test_imports.py
+++ b/pyflakes/test/test_imports.py
@@ -23,7 +23,7 @@ def test_usedImport(self):
         self.flakes('import fu; del fu')
 
     def test_redefinedWhileUnused(self):
-        self.flakes('import fu; fu = 3', m.RedefinedWhileUnused)
+        self.flakes('import fu; fu = 3; fu', m.RedefinedWhileUnused)
         self.flakes('import fu; fu, bar = 3', m.RedefinedWhileUnused)
         self.flakes('import fu; [fu, bar] = 3', m.RedefinedWhileUnused)
 
@@ -274,7 +274,7 @@ def fun(fu):
         ''')
 
     def test_newAssignment(self):
-        self.flakes('fu = None')
+        self.flakes('fu = None; fu')
 
     def test_usedInGetattr(self):
         self.flakes('import fu; fu.bar.baz')
@@ -448,7 +448,7 @@ def test_redefinedByExcept(self):
         self.flakes('''
         import fu
         try: pass
-        except Exception%sfu: pass
+        except Exception%sfu: fu
         ''' % as_exc, m.RedefinedWhileUnused)
 
     def test_usedInRaise(self):
@@ -482,7 +482,7 @@ def test_usedInKeywordArg(self):
         self.flakes('import fu; fu.bar(stuff=fu)')
 
     def test_usedInAssignment(self):
-        self.flakes('import fu; bar=fu')
+        self.flakes('import fu; bar=fu; bar')
         self.flakes('import fu; n=0; n+=fu')
 
     def test_usedInListComp(self):
@@ -725,7 +725,7 @@ def fu():
         ''', m.RedefinedWhileUnused)
 
     def test_ignoreNonImportRedefinitions(self):
-        self.flakes('a = 1; a = 2')
+        self.flakes('a = 1; a = 2; a')
 
     @skip("todo")
     def test_importingForImportError(self):
@@ -772,6 +772,7 @@ def test_futureImportFirst(self):
         self.flakes('''
         x = 5
         from __future__ import division
+        x
         ''', m.LateFutureImport)
         self.flakes('''
         from foo import bar
diff --git a/pyflakes/test/test_other.py b/pyflakes/test/test_other.py
index 0ac96a32..9f935eba 100644
--- a/pyflakes/test/test_other.py
+++ b/pyflakes/test/test_other.py
@@ -31,6 +31,7 @@ def test_redefinedInListComp(self):
         self.flakes('''
         a = 1
         [1 for a, b in [(1, 2)]]
+        a
         ''', m.RedefinedInListComp)
         self.flakes('''
         class A:
@@ -60,6 +61,7 @@ def test_redefinedInGenerator(self):
         self.flakes('''
         a = 1
         (1 for a, b in [(1, 2)])
+        a
         ''')
         self.flakes('''
         class A:
@@ -90,11 +92,13 @@ def test_redefinedInSetComprehension(self):
         self.flakes('''
         a = 1
         {1 for a, b in [(1, 2)]}
+        a
         ''')
         self.flakes('''
         class A:
             a = 1
             {1 for a, b in [(1, 2)]}
+            a
         ''')
         self.flakes('''
         def f():
@@ -120,6 +124,7 @@ def test_redefinedInDictComprehension(self):
         self.flakes('''
         a = 1
         {1: 42 for a, b in [(1, 2)]}
+        a
         ''')
         self.flakes('''
         class A:
@@ -220,6 +225,7 @@ def test_redefinedIfElseInListComp(self):
             a = 1
         else:
             [a for a in '12']
+        a
         ''')
 
     @skipIf(version_info >= (3,),
@@ -1020,6 +1026,7 @@ def test_doubleAssignment(self):
         self.flakes('''
         x = 10
         x = 20
+        x
         ''', m.RedefinedWhileUnused)
 
     def test_doubleAssignmentConditionally(self):
@@ -1031,6 +1038,7 @@ def test_doubleAssignmentConditionally(self):
         x = 10
         if True:
             x = 20
+        x
         ''')
 
     def test_doubleAssignmentWithUse(self):
@@ -1042,6 +1050,7 @@ def test_doubleAssignmentWithUse(self):
         x = 10
         y = x * 2
         x = 20
+        y
         ''')
 
     def test_comparison(self):
diff --git a/pyflakes/test/test_undefined_names.py b/pyflakes/test/test_undefined_names.py
index 5653b915..a28228b3 100644
--- a/pyflakes/test/test_undefined_names.py
+++ b/pyflakes/test/test_undefined_names.py
@@ -173,7 +173,6 @@ def test_delConditional(self):
         Ignores conditional bindings deletion.
         """
         self.flakes('''
-        context = None
         test = True
         if False:
             del(test)
@@ -256,6 +255,7 @@ def fun():
             a
             a = 2
             return a
+        a
         ''', m.UndefinedLocal)
 
     def test_laterRedefinedGlobalFromNestedScope2(self):
@@ -272,6 +272,7 @@ def fun2():
                     a
                     a = 2
                     return a
+            a
         ''', m.UndefinedLocal)
 
     def test_intermediateClassScopeIgnored(self):
@@ -507,6 +508,7 @@ def test_undefinedWithErrorHandler(self):
             socket_map
         except NameError:
             socket_map = {}
+        socket_map['foo'] = 1
         ''')
         self.flakes('''
         try:
@@ -520,12 +522,14 @@ def test_undefinedWithErrorHandler(self):
             socket_map
         except:
             socket_map = {}
+        socket_map['foo'] = 1
         ''', m.UndefinedName)
         self.flakes('''
         try:
             socket_map
         except Exception:
             socket_map = {}
+        socket_map['foo'] = 1
         ''', m.UndefinedName)
 
     def test_definedInClass(self):