diff --git a/cloud/openstack/os_volume.py b/cloud/openstack/os_volume.py
index 5a3d0aacab0..9e7436e1a5f 100644
--- a/cloud/openstack/os_volume.py
+++ b/cloud/openstack/os_volume.py
@@ -35,8 +35,9 @@ description:
 options:
    size:
      description:
-        - Size of volume in GB
-     required: only when state is 'present'
+        - Size of volume in GB. This parameter is required when the
+          I(state) parameter is 'present'.
+     required: false
      default: None
    display_name:
      description: