Malignant melanoma is the cutaneous cancer with the worst prognosis . It is one of the most quickly increasing cancers worldwide. It has been shown that expression of Ki-67, p53, and bcl-2 correlates with prognosis of various tumors. In the current study, expression of these three proteins was determined and correlated with clinical and histological parameters. Thus, 26 malignant melanomas were immunohistochemically stained with specific antibodies and the percentage of positive cells was determined. All malignant melanoma showed expression of Ki-67, p53, and bcl-2. There was a trend (p=0.08) towards increased Ki-67-expression in aneuploid compared to diploid tumors. Furthermore, p53-expression was significantly increased in tumors up to 1,5 mm thick and in superficial spreading melanoma compared to nodular melanoma. However, extensive variation could be observed within the single groups. All other parameters did not show significant differences between the groups. Taken together, determining expression of Ki-67, p53, and bcl-2 is probably not the optimal parameter to determine prognosis and define therapy of malignant melanoma. Other markers should be tested concerning their prognostic and therapeutic value.