Tumor vaccination is a form of an active specific immunotherapy that aims in the induction of a specific immune response against the tumor. In the last 30 years a great number of studies had been performed using native, not modified tumor cells or different methods of modifying tumor cells. In the last year viral xenogenization of tumor cells had been extensively examined in different studies. In gynecologic cancer patients it could be demonstrated that in a certain part of vaccinated patients an increase of specific cytotoxicity could be induced and that compared with historic controls, a benefit in ovarian cancer patients could be observed. There are further results showing that a pretreatment of tumor-bearing hosts prior to vaccination may enhance subsequent immune reactivity and enhance the susceptibility of tumor cells. This is the rationale of a combination of chemo- and immunotherapy.