The early clinical trials with interleukin-12 (IL-12) have demonstrated substantial toxicity of this cytokine. One way to resolve this problem would be to find other antitumor agents, e.g. chemotherapeutics, synergistically interacting with IL-12. However, analysis of the recent reports on this topic leads to the conclusion that the antitumor effects achieved in such combination treatments are dependent not only on the drug applied but also on the tumor model used. We described previously lack of the potentiation of antitumor effects in combination treatment with IL-12 and paclitaxel in a murine leukemia L1210 model. We investigated whether such treatment could bring therapeutical benefit by using the murine melanoma MmB16 model. significant potentiation of antitumor effects in combination treatment with IL-12 and paclitaxel was observed. These results suggest that combination of IL-12 and paclitaxel could be beneficial in the treatment of certain types of tumors.