diff --git a/README.rst b/README.rst
index 86e9ae3e..2f276ecf 100644
--- a/README.rst
+++ b/README.rst
@@ -60,14 +60,13 @@ Jedi supports many of the widely used Python features:
 - class decorators (py3k feature, are being ignored too, until I find a use
   case, that doesn't work with Jedi)
 - simple/usual ``sys.path`` modifications
-- ``isinstance`` checks for if/while
+- ``isinstance`` checks for if/while/assert
 
 However, it does not yet support (and probably will in future versions, because
 they are on my todo list):
 
 - manipulations of instances outside the instance variables, without using
   functions
-- assert
 
 It does not support (and most probably will not in future versions): 
 
diff --git a/jedi/dynamic.py b/jedi/dynamic.py
index 47316156..b113a5b7 100644
--- a/jedi/dynamic.py
+++ b/jedi/dynamic.py
@@ -494,18 +494,32 @@ class RelatedName(BaseOutput):
         return hash((self.start_pos, self.module_path))
 
 
-def check_flow_information(flow, search_name):
+def check_flow_information(flow, search_name, pos):
     """ Try to find out the type of a variable just with the information that
-    is given by the flows: e.g.
+    is given by the flows: e.g. It is also responsible for assert checks.
     >>> if isinstance(k, str):
     >>>     k.  # <- completion here
 
     ensures that `k` is a string.
     """
+    result = []
+    if isinstance(flow, parsing.Scope) and not result:
+        for ass in reversed(flow.asserts):
+            if ass.start_pos > pos:
+                continue
+            result = check_statement_information(ass, search_name)
+            if result:
+                break
+
+    if isinstance(flow, parsing.Flow) and not result:
+        if flow.command in ['if', 'while'] and len(flow.inits) == 1:
+            result = check_statement_information(flow.inits[0], search_name)
+    return result
+
+
+def check_statement_information(stmt, search_name):
     try:
-        assert flow.command in ['if', 'while']
-        assert len(flow.inits) == 1
-        ass = flow.inits[0].get_assignment_calls()
+        ass = stmt.get_assignment_calls()
         assert len(ass.values) == 1 and len(ass.values[0]) == 1
         call = ass.values[0][0]
         assert type(call) == parsing.Call and str(call.name) == 'isinstance'
diff --git a/jedi/evaluate.py b/jedi/evaluate.py
index c0502ba4..7a17b946 100644
--- a/jedi/evaluate.py
+++ b/jedi/evaluate.py
@@ -264,7 +264,7 @@ class Instance(use_metaclass(CachedMetaClass, Executable)):
 
     def __getattr__(self, name):
         if name not in ['start_pos', 'end_pos', 'name', 'get_imports',
-                                                                'docstr']:
+                                                        'docstr', 'asserts']:
             raise AttributeError("Instance %s: Don't touch this (%s)!"
                                     % (self, name))
         return getattr(self.base, name)
@@ -386,7 +386,7 @@ class Class(use_metaclass(CachedMetaClass, parsing.Base)):
 
     def __getattr__(self, name):
         if name not in ['start_pos', 'end_pos', 'parent', 'subscopes',
-                            'get_imports', 'get_parent_until', 'docstr']:
+                    'get_imports', 'get_parent_until', 'docstr', 'asserts']:
             raise AttributeError("Don't touch this (%s)!" % name)
         return getattr(self.base, name)
 
@@ -726,6 +726,11 @@ class Execution(Executable):
     def returns(self):
         return self.copy_properties('returns')
 
+    @property
+    @memoize_default()
+    def asserts(self):
+        return self.copy_properties('asserts')
+
     @property
     @memoize_default()
     def statements(self):
@@ -1148,10 +1153,13 @@ def get_scopes_for_name(scope, name_str, position=None, search_global=False,
             if result:
                 break
 
-            while flow_scope and flow_scope.isinstance(parsing.Flow):
-                result = dynamic.check_flow_information(flow_scope, name_str)
+            while flow_scope:
+                result = dynamic.check_flow_information(flow_scope, name_str,
+                                                                    position)
                 if result:
                     break
+                if flow_scope == nscope:
+                    break
                 flow_scope = flow_scope.parent()
             flow_scope = nscope
             if result:
diff --git a/jedi/helpers.py b/jedi/helpers.py
index 111d7f38..788f4f65 100644
--- a/jedi/helpers.py
+++ b/jedi/helpers.py
@@ -92,7 +92,7 @@ class ExecutionRecursionDecorator(object):
         self.reset()
 
     def __call__(self, execution, evaluate_generator=False):
-        debug.dbg('Execution recursions: ', execution, self.recursion_level,
+        debug.dbg('Execution recursions: %s' % execution, self.recursion_level,
                             self.execution_count, len(self.execution_funcs))
         if self.check_recursion(execution, evaluate_generator):
             result = []
diff --git a/jedi/parsing.py b/jedi/parsing.py
index 312336a0..1a4c2940 100644
--- a/jedi/parsing.py
+++ b/jedi/parsing.py
@@ -139,6 +139,7 @@ class Scope(Simple):
         self.imports = []
         self.statements = []
         self.docstr = docstr
+        self.asserts = []
 
     def add_scope(self, sub, decorators):
         sub.parent = weakref.ref(self)
@@ -1416,7 +1417,7 @@ class PyFuzzyParser(object):
                         string += ".".join(n.names)
                     continue
                 elif token_type == tokenize.NAME:
-                    if tok in ['return', 'yield', 'del', 'raise', 'assert']:
+                    if tok in ['return', 'yield', 'del', 'raise']:
                         if len(tok_list) > 1:
                             # this happens, when a statement has opening
                             # brackets, which are not closed again, here I just
@@ -1751,6 +1752,10 @@ class PyFuzzyParser(object):
                     decorators.append(stmt)
                 elif tok == 'pass':
                     continue
+                elif tok == 'assert':
+                    stmt, tok = self._parse_statement()
+                    stmt.parent = weakref.ref(self.scope)
+                    self.scope.asserts.append(stmt)
                 # default
                 elif token_type in [tokenize.NAME, tokenize.STRING,
                                     tokenize.NUMBER] \
diff --git a/test/completion/isinstance.py b/test/completion/isinstance.py
index db0a4e4f..01d1f7a5 100644
--- a/test/completion/isinstance.py
+++ b/test/completion/isinstance.py
@@ -17,3 +17,14 @@ if not isinstance(k, (str, int)):
 while not isinstance(k, (str, int)):
     #? 
     k
+
+assert isinstance(ass, int):
+#? int()
+ass
+
+assert isinstance(ass, str):
+assert not isinstance(ass, int):
+
+if 2:
+    #? str()
+    ass