diff --git a/CHANGES/2668.bugfix b/CHANGES/2668.bugfix
new file mode 100644
index 00000000000..e9176354c45
--- /dev/null
+++ b/CHANGES/2668.bugfix
@@ -0,0 +1 @@
+Do percent encoding for `.url_for()` parameters
\ No newline at end of file
diff --git a/CHANGES/2668.removal b/CHANGES/2668.removal
new file mode 100644
index 00000000000..809d533c196
--- /dev/null
+++ b/CHANGES/2668.removal
@@ -0,0 +1 @@
+Forbid non-strings in `resource.url_for()` parameters.
\ No newline at end of file
diff --git a/aiohttp/web_urldispatcher.py b/aiohttp/web_urldispatcher.py
index a444b67c708..83b3c9c4a94 100644
--- a/aiohttp/web_urldispatcher.py
+++ b/aiohttp/web_urldispatcher.py
@@ -405,8 +405,7 @@ def _match(self, path):
             return None
         else:
             return {key: URL.build(path=value, encoded=True).path
-                    for key, value in
-                    match.groupdict().items()}
+                    for key, value in match.groupdict().items()}
 
     def raw_match(self, path):
         return self._formatter == path
@@ -416,7 +415,8 @@ def get_info(self):
                 'pattern': self._pattern}
 
     def url_for(self, **parts):
-        url = self._formatter.format_map(parts)
+        url = self._formatter.format_map({k: URL.build(path=v).raw_path
+                                          for k, v in parts.items()})
         return URL.build(path=url)
 
     def __repr__(self):
diff --git a/tests/test_urldispatch.py b/tests/test_urldispatch.py
index 86d64044da7..293225d3e60 100644
--- a/tests/test_urldispatch.py
+++ b/tests/test_urldispatch.py
@@ -604,10 +604,18 @@ def test_route_dynamic_with_regex(router):
     handler = make_handler()
     route = router.add_route('GET', r'/{one}/{two:.+}', handler)
 
-    url = route.url_for(one=1, two=2)
+    url = route.url_for(one='1', two='2')
     assert '/1/2' == str(url)
 
 
+def test_route_dynamic_quoting(router):
+    handler = make_handler()
+    route = router.add_route('GET', r'/{arg}', handler)
+
+    url = route.url_for(arg='1 2/текст')
+    assert '/1%202/%D1%82%D0%B5%D0%BA%D1%81%D1%82' == str(url)
+
+
 async def test_regular_match_info(router):
     handler = make_handler()
     router.add_route('GET', '/get/{name}', handler)