Seventy-five cases of acute haemorrhagic conjunctivitis (A.H.C.) were subjected to full ophthalmic, bacteriological, virological, serological as well as cytological examinations. The majority of cases presented with bilateral conjunctivitis (70 out of 75). Although follicular reaction was the earliest sign, yet subconjunctival haemorrhages were the most constant findings in all the cases. Enterovirus 70 was isolated in 57 cases from conjunctival swabs and in 43 cases from serum samples. Complement flaxation test was positive for enterovirus 70 in 42 cases but negative for coxsackie and adenoviruses. No primary role has been found for bacteria in the pathogenesis of A.H.C. in this outbreak. Cytological examination of conjunctival scrappings showed the characteristics cytopathic effect (CPE) of enteroviruses.