diff --git a/CHANGES/2278.removal b/CHANGES/2278.removal
new file mode 100644
index 00000000000..9e5a9983c37
--- /dev/null
+++ b/CHANGES/2278.removal
@@ -0,0 +1 @@
+Deprecate modification of ``session.requote_redirect_url``
diff --git a/aiohttp/client.py b/aiohttp/client.py
index 06981b31404..fd2b71eedd7 100644
--- a/aiohttp/client.py
+++ b/aiohttp/client.py
@@ -98,8 +98,6 @@ class ClientSession:
     _source_traceback = None
     _connector = None
 
-    requote_redirect_url = True
-
     def __init__(self, *, connector: Optional[BaseConnector]=None,
                  loop: Optional[asyncio.AbstractEventLoop]=None,
                  cookies: Optional[LooseCookies]=None,
@@ -119,6 +117,7 @@ def __init__(self, *, connector: Optional[BaseConnector]=None,
                  timeout: Union[object, ClientTimeout]=sentinel,
                  auto_decompress: bool=True,
                  trust_env: bool=False,
+                 requote_redirect_url: bool=True,
                  trace_configs: Optional[List[TraceConfig]]=None) -> None:
 
         if loop is None:
@@ -171,6 +170,7 @@ def __init__(self, *, connector: Optional[BaseConnector]=None,
         self._raise_for_status = raise_for_status
         self._auto_decompress = auto_decompress
         self._trust_env = trust_env
+        self._requote_redirect_url = requote_redirect_url
 
         # Convert to list of tuples
         if headers:
@@ -468,7 +468,7 @@ async def _request(
 
                         try:
                             r_url = URL(
-                                r_url, encoded=not self.requote_redirect_url)
+                                r_url, encoded=not self._requote_redirect_url)
 
                         except ValueError:
                             raise InvalidURL(r_url)
@@ -841,6 +841,20 @@ def version(self) -> Tuple[int, int]:
         """The session HTTP protocol version."""
         return self._version
 
+    @property
+    def requote_redirect_url(self) -> bool:
+        """Do URL requoting on redirection handling."""
+        return self._requote_redirect_url
+
+    @requote_redirect_url.setter
+    def requote_redirect_url(self, val: bool) -> None:
+        """Do URL requoting on redirection handling."""
+        warnings.warn("session.requote_redirect_url modification "
+                      "is deprecated #2778",
+                      DeprecationWarning,
+                      stacklevel=2)
+        self._requote_redirect_url = val
+
     @property
     def loop(self) -> asyncio.AbstractEventLoop:
         """Session's loop."""
diff --git a/docs/client_reference.rst b/docs/client_reference.rst
index fd1bf2c3604..cfa8d7b11be 100644
--- a/docs/client_reference.rst
+++ b/docs/client_reference.rst
@@ -48,7 +48,10 @@ The client session supports the context manager protocol for self closing.
                          timeout=sentinel, \
                          raise_for_status=False, \
                          connector_owner=True, \
-                         auto_decompress=True, proxies=None)
+                         auto_decompress=True, \
+                         requote_redirect_url=False, \
+                         trust_env=False, \
+                         trace_configs=None)
 
    The class for creating client sessions and making requests.
 
@@ -176,6 +179,17 @@ The client session supports the context manager protocol for self closing.
 
          Added support for ``~/.netrc`` file.
 
+   :param bool requote_redirect_url: Apply *URL requoting* for redirection URLs if
+                                     automatic redirection is enabled (``True`` by
+                                     default).
+
+      .. versionadded:: 3.5
+
+   :param trace_configs: A list of :class:`TraceConfig` instances used for client
+                         tracing.  ``None`` (default) is used for request tracing
+                         disabling.  See :ref:`aiohttp-client-tracing-reference` for
+                         more information.
+
    .. attribute:: closed
 
       ``True`` if the session has been closed, ``False`` otherwise.
@@ -207,6 +221,10 @@ The client session supports the context manager protocol for self closing.
 
       .. note:: This parameter affects all subsequent requests.
 
+      .. deprecated:: 3.5
+
+         The attribute modification is deprecated.
+
    .. attribute:: loop
 
       A loop instance used for session creation.
diff --git a/tests/test_client_session.py b/tests/test_client_session.py
index 3934aab308f..6c48728060f 100644
--- a/tests/test_client_session.py
+++ b/tests/test_client_session.py
@@ -687,3 +687,21 @@ async def test_client_session_timeout_args(loop) -> None:
         ClientSession(loop=loop,
                       timeout=client.ClientTimeout(total=10 * 60),
                       conn_timeout=30 * 60)
+
+
+async def test_requote_redirect_url_default() -> None:
+    session = ClientSession()
+    assert session.requote_redirect_url
+
+
+async def test_requote_redirect_url_default_disable() -> None:
+    session = ClientSession(requote_redirect_url=False)
+    assert not session.requote_redirect_url
+
+
+async def test_requote_redirect_setter() -> None:
+    session = ClientSession()
+    assert session.requote_redirect_url
+    with pytest.warns(DeprecationWarning):
+        session.requote_redirect_url = False
+    assert not session.requote_redirect_url