Melanoma is the fastest growing solid tumor in men and women, and despite accounting for only 4% of skin cancer cases, it accounts for more than 79% of skin cancer-related deaths. The present study was designed to evaluate the impact of interferon (IFN) treatment on patients' quality of life (QOL) after radical surgery of cutaneous melanoma. The tests were carried out in a group of patients treated in the Department of Soft Tissue and Bone Cancer, Institute of Oncology, in Warsaw. The present study included 2 groups of the patients, 110 persons each. One group consisted of patients who had been subjected to radical surgery of cutaneous melanoma, and the other one consisted of 110 patients treated with a supplementary interferon alfa-2b (IFN-alpha-2b) therapy. Data were collected by means of an anonymous QLQ-C30 (version 2.0.) questionnaire elaborated and provided by the European Organisation for Research and Treatment of Cancer. The QLQ-C30 questionnaire consisted of 43 questions. The IFN-alpha-2b treatment significantly affected patients' physical condition, mental health, and social life. The emotional state of the patients was more affected during IFN-alpha-2b treatment. Somatic symptoms were also increased in those patients. The IFN-alpha-2b therapy also significantly affected family and social life. In spite of several adverse effects, the patients assessed their QOL as good. The IFN-alpha-2b treatment is troublesome for the melanoma patients. It is important that the treating physician and nurse should be aware of the 4 major categories of IFN-alpha-2b toxicity: constitutional, neuropsychiatric, hepatic, and hematologic. A number of steps can be taken to minimize the morbidity associated with IFN-alpha-2b therapy, resulting in an improvement in both QOL and patient compliance.