Helicobacter pylori infection induces an important systemic and mucosal antibody response and a predominant Th1 cellular response. These immune responses, although powerful, fail to eliminate the infection. Studies in animals have shown that prophylactic and therapeutic immunisations are efficacious, although complete protective immunity has usually not been achieved. Initial human trials with recombinant urease showed that a mucosal immune response can be obtained following immunisations, with a decrease in bacterial density, but successful immunisation is still awaited. Progress is being made in several areas of vaccine design. A human vaccine against H. pylori would be favourable in terms of health benefits and costs in developed and developing countries.