A live oral Vibrio cholerae O1 El Tor vaccine, Peru-15 was tested in a double-blind, randomized placebo controlled study for safety and immunogenicity in Phase I and Phase II studies in 240 Bangladeshi children aged 9 months–5 years of age. Two different doses (2×10⁷ and 2×10⁸cfu) were tested. Vaccination did not elicit adverse events and the strain was genetically stable. Vibriocidal antibody responses developed in 42/50 (84%) toddlers (2–5 years) and 35/50 (70%) of younger children (9–23 months) and overall 77/100 (77%) who received the high dose. LPS-IgA-antibody responses were seen in 60% of toddlers and 34% of infants; 40% responded with IgA antibodies to cholera toxin. The responses to the reduced dose was lower. These studies demonstrate that Peru-15 at a dose of 2×10⁸cfu is safe and immunogenic in children in Bangladesh.