Bergamasco made his international debut against France in the 2002 Six Nations Championship, having previously appeared against an All-Star XV in a non-cap international. He established himself as a regular in the Azzurri side under coach John Kirwan. He scored three tries in the 2003 Six Nations Championship. He suffered a jaw injury during the 2003 Rugby World Cup, however, and was forced to miss all but two of Italy's games.