Melanoma with a tumor thickness >= 1.5mm without clinically detectable nodes represents an increasing population with relapse rate of more than 50%. Adjuvant therapy with low doses of IFN alpha can provide a benefit in this group. However, the impact of low dose IFN alpha is not sustained after the treatment period. A longer treatment may prolong the benefit and thus have a more clear-cut impact on disease-free and overall survival. The tolerance and the impact on quality of life are limiting factors in a group of patients whose individual course is not necessarily poor. PegIntron may be better tolerated than instant release interferon, and thus make this treatment more acceptable in terms of toxicity and quality of life. Thus treatment schedule with PegIntron is not expected to increase the cost of standard care significantly.