This retrospective investigation concerns 212 cases of malignant melanoma from the period 1965 to 1979. Before operation 53 cases were given radiation therapy. The aim of the study was to assess whether this treatment had any influence on survival. Clinical follow-up and revision of the histologic material has been done. The tumours were classified according to CLARK et coll. (3) and divided into thickness groups (2). Statistical analysis by COX's regression model (4) indicated that survival was dependent on tumour thickness (significance level 1%) and preoperative irradiation (significance level 5%). No influence from tumour location was noted. A prospective randomized study is proposed in order to analyse the effect of preoperative irradiation.