diff --git a/jedi/api/refactoring.py b/jedi/api/refactoring.py
index cd51d261..f39aeb6d 100644
--- a/jedi/api/refactoring.py
+++ b/jedi/api/refactoring.py
@@ -384,12 +384,12 @@ def extract_function(inference_state, path, module_context, name, pos, until_pos
     is_expression = True
     nodes = _find_nodes(module_context.tree_node, pos, until_pos)
     return_variables = []
-    params = _find_non_global_names(nodes)
+    context = module_context.create_context(nodes[0])
+    params = list(_find_non_global_names(context, nodes))
 
     dct = {}
     # Find variables
     # Is a class method / method
-    context = module_context.create_context(nodes[0])
     if context.is_module():
         insert_before_leaf = None  # Leaf will be determined later
     else:
@@ -424,8 +424,16 @@ def extract_function(inference_state, path, module_context, name, pos, until_pos
     return Refactoring(inference_state.grammar, file_to_node_changes)
 
 
-def _find_non_global_names(nodes):
-    return []
+def _find_non_global_names(context, nodes):
+    for node in nodes:
+        try:
+            children = node.children
+        except AttributeError:
+            if node.type == 'name':
+                yield node.value
+        else:
+            for x in _find_non_global_names(context, children):  # Python 2...
+                yield x
 
 
 def _get_code_insertion_node(context):
diff --git a/test/refactor/extract_function.py b/test/refactor/extract_function.py
index d3e0127f..3941fabe 100644
--- a/test/refactor/extract_function.py
+++ b/test/refactor/extract_function.py
@@ -3,11 +3,11 @@
 test(100, (30 + b, c) + 1)
 # ++++++++++++++++++++++++++++++++++++++++++++++++++
 #? 11 text {'new_name': 'a'}
-def a():
+def a(b):
     return 30 + b
 
 
-test(100, (a(), c) + 1)
+test(100, (a(b), c) + 1)
 # -------------------------------------------------- in-module-2
 #? 0 text {'new_name': 'ab'}
 100 + 1 * 2
@@ -23,27 +23,27 @@ def f(x):
 #? 11 text {'new_name': 'ab'}
     return x + 1 * 2
 # ++++++++++++++++++++++++++++++++++++++++++++++++++
-def ab():
+def ab(x):
     return x + 1 * 2
 
 
 def f(x):
 #? 11 text {'new_name': 'ab'}
-    return ab()
+    return ab(x)
 # -------------------------------------------------- in-function-with-dec
 @classmethod
 def f(x):
 #? 11 text {'new_name': 'ab'}
     return x + 1 * 2
 # ++++++++++++++++++++++++++++++++++++++++++++++++++
-def ab():
+def ab(x):
     return x + 1 * 2
 
 
 @classmethod
 def f(x):
 #? 11 text {'new_name': 'ab'}
-    return ab()
+    return ab(x)
 # -------------------------------------------------- in-method-1
 class X:
     def z(self): pass
@@ -55,12 +55,12 @@ class X:
 class X:
     def z(self): pass
 
-    def ab():
+    def ab(x):
         return x + 1 * 2
 
     def f(x):
         #? 11 text {'new_name': 'ab'}
-        return ab()
+        return ab(x)
 # -------------------------------------------------- in-classmethod-1
 class X:
     @classmethod
@@ -98,11 +98,11 @@ class Ya():
     #? 11 text {'new_name': 'f'}
     c = a + 2
 # ++++++++++++++++++++++++++++++++++++++++++++++++++
-def f():
+def f(a):
     return a + 2
 
 
 class Ya():
     a = 3
     #? 11 text {'new_name': 'f'}
-    c = f()
+    c = f(a)