diff --git a/CHANGES/2688.doc b/CHANGES/2688.doc
new file mode 100644
index 00000000000..1298f9fd668
--- /dev/null
+++ b/CHANGES/2688.doc
@@ -0,0 +1 @@
+Fixed mistype in `Proxy Support` section where `trust_env` parameter was used in `session.get("http://python.org", trust_env=True)` method instead of aiohttp.ClientSession constructor as follows: `aiohttp.ClientSession(trust_env=True)`.
diff --git a/docs/client_advanced.rst b/docs/client_advanced.rst
index 5e4957d09db..2c4b19624ee 100644
--- a/docs/client_advanced.rst
+++ b/docs/client_advanced.rst
@@ -498,8 +498,8 @@ constructor for extracting proxy configuration from
 *HTTP_PROXY* or *HTTPS_PROXY* *environment variables* (both are case
 insensitive)::
 
-   async with aiohttp.ClientSession() as session:
-       async with session.get("http://python.org", trust_env=True) as resp:
+   async with aiohttp.ClientSession(trust_env=True) as session:
+       async with session.get("http://python.org") as resp:
            print(resp.status)
 
 Proxy credentials are given from ``~/.netrc`` file if present (see