Because the primary aim of adjuvant therapy for melanoma is not curative, all the possible aspects of quality of life have to be considered. One aspect of increasing importance is fertility. The effect of adjuvant interferon alpha-therapy for malignant melanoma on male fertility has not been systematically investigated. In the present study, twelve male patients with primary cutaneous melanoma (pT3, 4; N0; M0) who were taking adjuvant low-dose interferon alpha2b (3 x 3 mio U/week) for one year were included. Inhibin B--an established marker of male fertility-was measured with an immunosorbent assay before and after one year of interferon alpha-therapy to investigate whether this treatment has any influence on fertility. The results were compared with those from normal controls (n=40). The mean serum inhibin B concentration in melanoma patients before interferon therapy was 225.4 +/- 112.5 pg/mL; after treatment the level was 229.6 +/- 82.0 pg/mL. This difference was not statistically significant (p>0.05). The serum inhibin B concentration in controls was 201.5 +/- 17.1 pg/mL, which was not statistically different from either untreated or interferon-treated melanoma patients (p>0.05). We conclude that low-dose interferon alpha does not have a significant (negative) effect on inhibin B or male fertility.