This study focused on the prevalence of V.cholerae O1 infection in 1,196 individuals living in Manacapuru, Amazonas State, through microtitering of vibriocidal antibody and somatic agglutination test. The role of living conditions and individual characteristics as possible risk factors for infection was also assessed. Vibriocidal titers or = 1: 40 and/or agglutinating titers or = 1: 80 were considered indicators of V.cholerae O1 infection. Infection prevalence was 25.7%. There was no significant statistical difference (p = 0.05) when analyzed against housing patterns, sanitary facilities, source and treatment of water, destination of domestic waste, sex, or profession. Household location, number of occupants/household, age, and schooling showed significant statistical differences in infection prevalence (p = 0.05).