The last 10 years have seen a growth in the number of tumour antigens identified from immune responses raised in patients. The discovery that tumours can be recognised by the immune system stimulated a great deal of work characterising the molecular mechanisms underlying immune recognition. This in turn has led to an impressive array of immunological approaches to the generation of cancer vaccines; these range from molecularly defined T cell epitopes, antibody-based vaccines, cytokine therapies, immune modulators and DNA vaccines, to whole cell vaccines and, more recently, combinations of these methods. Many of these approaches have entered Phase I/II trials and have shown interesting clinical results. Moreover, they have extended our knowledge of the immune system and our understanding of the mechanisms required to design a successful cancer vaccine. This review outlines some of the approaches that have led to some of these vaccines entering Phase III clinical trials, discusses their modes of action and reports on their current status in trial.