Cognomen ปิยวัจนพงศ์ (ปิยวัจนพงศ์ 
) , throughout the world, is a very rare last name. The last name ปิยวัจนพงศ์ is characteristic of South-eastern Asia, particularly Thailand, where it is a very rare surname.
| VARIANT | COUNTRY |
|---|---|
| ปิยวัจนพงศ์ | Thailand |