Since 1967 a total of 2403 patients with malignant melanoma have been treated according to a standardized regimen. The five-year survival rate for all patients in stage I was 79%. It was clearly dependent on tumour thickness or prognostic index, respectively. If tumour thickness was less than 0.75 mm or the prognostic index under 6, more than 90% survived for five years. With a tumour thickness of more than 3 mm or a prognostic index of greater than 13 the survival rate decreased to about 50%. Irrespective of tumour thickness the first signs of progression were local recurrence (20%), lymph-node metastases (50%), or distal metastases (30%). In case of progression symptoms recurred in about 80% within the first three years after tumour removal, in about 90% within five years. However, some 10% of progression signs occurred after more than five years. Prognosis was not significantly improved in stage I by adjuvant treatment with dacarbazine and BCG. In stage II the five-year survival rate was still about 30%. But in stage III only those patients with exclusively cutaneous distal metastases had a somewhat better prognosis. Only a few patients lived more than three years after the occurrence of organ metastases.