diff --git a/doc/source/io.rst b/doc/source/io.rst
index c5b7eff292722..aa2484b0cb5c3 100644
--- a/doc/source/io.rst
+++ b/doc/source/io.rst
@@ -168,7 +168,8 @@ General Parsing Configuration
 
 dtype : Type name or dict of column -> type, default ``None``
   Data type for data or columns. E.g. ``{'a': np.float64, 'b': np.int32}``
-  (unsupported with ``engine='python'``). Use `str` or `object` to preserve and
+  (unsupported with ``engine='python'``). Use `str` or `object` together
+  with suitable ``na_values`` settings to preserve and
   not interpret dtype.
 
   .. versionadded:: 0.20.0 support for the Python parser.
diff --git a/pandas/io/parsers.py b/pandas/io/parsers.py
index 780aa5d02f598..2c8f98732c92f 100755
--- a/pandas/io/parsers.py
+++ b/pandas/io/parsers.py
@@ -125,7 +125,8 @@
     are duplicate names in the columns.
 dtype : Type name or dict of column -> type, default None
     Data type for data or columns. E.g. {'a': np.float64, 'b': np.int32}
-    Use `str` or `object` to preserve and not interpret dtype.
+    Use `str` or `object` together with suitable `na_values` settings
+    to preserve and not interpret dtype.
     If converters are specified, they will be applied INSTEAD
     of dtype conversion.
 %s