A double-blind randomised phase III trial of the reformulated oral killed bivalent cholera vaccine in an urban slum site in Kolkata is proposed by the National Institute of Cholera and Enteric Diseases (NICED) in collaboration with the International Vaccine Institute (IVI). The IVI has negotiated an agreement between VABIOTECH and Shantha Biotechnics PVT LTD for the vaccine and placebo to be used during the trial. VABIOTECH will produce bulk oral killed bivalent cholera vaccine under quality control conditions to be supervised by IVI staff. Shanta will purchase bulk vaccine from VABIOTECH, fill and finish the bulk vaccine, and obtain regulatory clearance for use of the vaccine in the phase III trial. Shanta will purchase the bulk placebo agent for use in the trial from IVAC (also in Vietnam) and Shanta will fill and finish the placebo and obtain regulatory clearance for use of the placebo in the phase III trial. Shanta will later obtain the technology for future production of the oral killed bivalent cholera vaccine. The results of this trial will pave the way for the use of this vaccine in India and other cholera-endemic areas.