A new type of acute keratoconjunctivitis developed throughout Southeast Asia, beginning in Singapore in the summer of 1970. It was highly contagious and probably was transmitted from person to person by the hand to eye route. Sixteen cases, diagnosed by viral isolation or serologic study, or both, were subjected to detailed clinical observation. The characteristic features included a short incubation period of one or two days, watery or serous discharge, subconjunctival hemorrhage, and pinpoint superficial keratopathy. The disease usually resolved rapidly within one to two weeks without sequelae.