During a community outbreak of epidemic keratoconjunctivitis due to adenovirus types 8 and 19, we compared the clinical and laboratory characteristics of the two viruses. Much of the disease was mild and the keratoconjunctivitis associated with adenovirus type 8 was indistinguishable clinically from that associated with adenovirus type 19. Adenovirus type 8 was isolated only from the conjunctival sac, whereas adenovirus type 19 was frequently cultured from the nose, throat, and conjunctiva. The two adenovirus types were never isolated from the same individual. In a prospective study of ten individuals exposed to known cases, adenovirus type 19 was isolated from two without clinical disease.