diff --git a/MANIFEST.in b/MANIFEST.in
index 0a189be..fdfa9f5 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -4,3 +4,6 @@ include propka.cfg
 
 include versioneer.py
 include propka/_version.py
+
+# Python type annotation declarations, see PEP-561
+include propka/py.typed
diff --git a/propka/py.typed b/propka/py.typed
new file mode 100644
index 0000000..e69de29