A total of seventy-six patients with cutaneous malignant melanoma were analysed with relation to the prognostic influence of incisional biopsies. Of these, sixty-two underwent primary radical surgery, whereas fourteen patients had an incisional procedure prior to definitive treatment. Multivariate analysis revealed that survival was markedly reduced after incisional procedures. Other important prognostic factors were ulceration, age and sex. We believe that punch or incisional biopsies taken to substantiate the diagnosis of melanoma should be avoided.