Incidence of Vibrio cholerae O1 was studied in 2,585 samples from different aquatic environments and 91 from foods in Pernambuco State, northeastern Brazil, from 1992 to 1994. A total of 193 (7.21%) samples of V. cholerae were isolated with a higher prevalence of the Inaba serovar (183-94.8%) than the Ogawa serotype (10-5.1%). All isolates were classified as biotype El Tor, and resistance patterns to antibiotics showed that all strains were susceptible tetracycline. Some 70 random samples of Vibrio cholerae proved toxigenic, including all the Ogawa serovars. Incidence of V. cholerae O1 in river water and sewage (86.0%) pointed to fecal contamination as the most common source and vehicle for rapid spread of the microorganism in the aquatic environment. The vibrio was isolated in 2.1% of all food examined, which was less than expected.