diff --git a/stdlib/2.7/itertools.pyi b/stdlib/2.7/itertools.pyi
index fe2fa9cc4..14ab5aecd 100644
--- a/stdlib/2.7/itertools.pyi
+++ b/stdlib/2.7/itertools.pyi
@@ -3,7 +3,7 @@
 # Based on https://docs.python.org/2/library/itertools.html
 
 from typing import (Iterator, TypeVar, Iterable, overload, Any, Callable, Tuple,
-                    Union, Sequence)
+                    Union, Sequence, Generic)
 
 _T = TypeVar('_T')
 _S = TypeVar('_S')
@@ -15,8 +15,12 @@ def cycle(iterable: Iterable[_T]) -> Iterator[_T]: ...
 def repeat(object: _T, times: int = ...) -> Iterator[_T]: ...
 
 def accumulate(iterable: Iterable[_T]) -> Iterator[_T]: ...
-def chain(*iterables: Iterable[_T]) -> Iterator[_T]: ...
-# TODO chain.from_Iterable
+
+class chain(Iterator[_T], Generic[_T]):
+    def __init__(self, *iterables: Iterable[_T]) -> None: ...
+    @staticmethod
+    def from_iterable(iterable: Iterable[Iterable[_T]]) -> Iterator[_T]: ...
+
 def compress(data: Iterable[_T], selectors: Iterable[Any]) -> Iterator[_T]: ...
 def dropwhile(predicate: Callable[[_T], Any],
               iterable: Iterable[_T]) -> Iterator[_T]: ...
diff --git a/stdlib/3/itertools.pyi b/stdlib/3/itertools.pyi
index cb219b431..6c159e330 100644
--- a/stdlib/3/itertools.pyi
+++ b/stdlib/3/itertools.pyi
@@ -3,7 +3,7 @@
 # Based on http://docs.python.org/3.2/library/itertools.html
 
 from typing import (Iterator, TypeVar, Iterable, overload, Any, Callable, Tuple,
-                    Union, Sequence)
+                    Union, Sequence, Generic)
 
 _T = TypeVar('_T')
 _S = TypeVar('_S')
@@ -18,8 +18,12 @@ def repeat(object: _T) -> Iterator[_T]: ...
 def repeat(object: _T, times: int) -> Iterator[_T]: ...
 
 def accumulate(iterable: Iterable[_T]) -> Iterator[_T]: ...
-def chain(*iterables: Iterable[_T]) -> Iterator[_T]: ...
-# TODO chain.from_Iterable
+
+class chain(Iterator[_T], Generic[_T]):
+    def __init__(self, *iterables: Iterable[_T]) -> None: ...
+    @staticmethod
+    def from_iterable(iterable: Iterable[Iterable[_T]]) -> Iterator[_T]: ...
+
 def compress(data: Iterable[_T], selectors: Iterable[Any]) -> Iterator[_T]: ...
 def dropwhile(predicate: Callable[[_T], Any],
               iterable: Iterable[_T]) -> Iterator[_T]: ...