In the last century, it has become clear that in patients suffering certain types of cancer, spontaneous activation of the immune sytem may lead to curation. The concept of immunotherapy is based on that notion. The intention is to stimulate T cells directed against the cancer, leading to the eradication of cancer cells. However, the methods to stimulate T cell immunity are just evolving, and at the moment they are functional in small laboratory animals only. Furthermore, we know now that many cancer cells possess the capacity to scive attacks of the immune system. This thesis introduces a novel T cell vaccination method that uses a tattoo machine to inject DNA in the skin of the vaccinee. In comparison to other experimental vaccination methods DNA tattooing is very strong: besides small laboratry animals also large animals (mockeys) mount strong T cell responses on tattoo DNA vaccination. Future tests in melanoma patients will point out whether DNA tattoo vaccination is equally efficient in humans, and whether it may have a therapeutic effect in these patients.