Surgery is still the primary treatment for cutaneous malignant melanoma. During the last 15 years randomized studies have given information on how to excise and we know now that thin melanomas (up to 2.0 mm in thickness) can be treated with 1-2 cm excision margins. Whether this is also true for thicker melanomas is not known and the only way to obtain more knowledge is to participate in prospective randomized studies. These have to be large due to the expected low difference in outcome or no difference in outcome between groups. The studies also involve adjuvant treatment of different types. No treatment in series, with large numbers and long follow-up, has shown improved overall survival compared with the control arm when different adjuvant therapies are given. Palliative treatment of disseminated melanoma has shown increasing response rates with combination chemotherapy and/or treatment with immune response modifiers but more data are needed. Clinicians with responsibility for patients with malignant melanoma and with an interest in improving outcome and quality of life should participate in ongoing clinical trials. Only with large prospective randomized trials of the design described in this article, will our knowledge increase for the benefit of our patients.