The man, who was in his 30s, died at the scene of the crash on the N25 between New Ross and Ballinaboola.
The van driver and his two passengers were uninjured in the crash, which took place at 12.50pm.
Gardaí have appealed for witnesses to contact New Ross Garda station on 051 426030 or the Garda Confidential line on 1800 666 111.