To predict the expected lifetimes of nuclear waste containers under Canadian disposal vault conditions, specific criteria upon which a predictive model can be based must be developed. The anticipated evolution of the corrosion of titanium waste containers is described. Failure is most likely to occur by a combination of crevice corrosion, hydrogen-induced cracking and general corrosion and, for long lifetimes, the duration of crevice corrosion must be limited. The crevice corrosion of Grade-2 and Grade-12 titanium has been studied using a galvanic coupling technique. The propagation of crevice corrosion on the Grade-2 material is dependent on both temperature and oxygen concentration and repassivation occurs once the oxygen is consumed. The propagation of crevice corrosion on the Grade-12 alloy appears almost independent of temperature, and repassivation occurs for T ⩽73°C even in the presence of copious amounts of oxygen. The implications for predicting the lifetimes of containers under disposal conditions are discussed.