Virus survival in the laboratory was examined in non sterile and sterile seawater. Five enteric viruses were studied (Poliovirus, Coxsackie A and B) at four temperatures 4, 12, 22, 37 degrees. Thirty to forty days were required for a 3 log (99.9%) reduction at 22 degrees C, without regard to the virus type, in sterile seawater. Survival times were longer at lower temperatures, but shorter in non sterile seawater. A correlation between virus inactivation and particles of natural seawaters was suggested.