diff --git a/src/hackney_http.erl b/src/hackney_http.erl
index d37b5f93..d2d19931 100644
--- a/src/hackney_http.erl
+++ b/src/hackney_http.erl
@@ -232,7 +232,12 @@ parse_status(<< C, Rest/bits >>, St, Version, Acc) ->
   end.
 
 parse_reason(Reason, St, Version, StatusCode) ->
-  StatusInt = list_to_integer(binary_to_list(StatusCode)),
+  %% Handle non-standard decimal status codes (e.g., 401.1 from IIS) by truncating
+  StatusCodeInt = case binary:split(StatusCode, <<".">>) of
+    [IntPart, _DecPart] -> IntPart;
+    [IntPart] -> IntPart
+  end,
+  StatusInt = list_to_integer(binary_to_list(StatusCodeInt)),
 
   NState = St#hparser{type=response,
     version=Version,
diff --git a/test/hackney_http_tests.erl b/test/hackney_http_tests.erl
index 4b7e7315..a1fed2e4 100644
--- a/test/hackney_http_tests.erl
+++ b/test/hackney_http_tests.erl
@@ -66,3 +66,18 @@ parse_chunked_response_trailers_test() ->
 	{_, P3} = hackney_http:execute(P2, <<"\r\n">>),
 	{more, P4} = hackney_http:execute(P3, <<"0\r\nFoo: ">>),
 	?assertEqual({done, <<>>}, hackney_http:execute(P4, <<"Bar\r\n\r\n">>)).
+
+%% Issue #697: Handle non-standard decimal status codes (e.g., 401.1 from IIS)
+parse_response_decimal_status_code_test() ->
+	Response = <<"HTTP/1.1 401.1 Access Denied">>,
+	St = #hparser{},
+	{response, _Version, StatusInt, Reason, _NState} = hackney_http:parse_response_version(Response, St),
+	?assertEqual(401, StatusInt),
+	?assertEqual(<<"Access Denied">>, Reason).
+
+parse_response_decimal_status_code_two_digits_test() ->
+	Response = <<"HTTP/1.1 403.14 Forbidden">>,
+	St = #hparser{},
+	{response, _Version, StatusInt, Reason, _NState} = hackney_http:parse_response_version(Response, St),
+	?assertEqual(403, StatusInt),
+	?assertEqual(<<"Forbidden">>, Reason).