[en] Fraction size in radiotherapy of malignant melanoma remains a point of controversy. Among 139 patients treated at the University of Illinois Hospital in 1979-1988, 36 were considered potentially curable (not counting ocular melanomas); 20 were treated by the Princess Margaret Hospital (PMH) hypofractionated schedule using 800 cGy per fraction and achieved a permanency of local control lasting > 6 months since the beginning of radiotherapy in 10/22 (45.5%) courses. Comparable results were obtained in 11 patients treated by standard fractionation to at least threshold curative levels. A modification of PMH regimen in 5 patients (but with 13 courses) by decreasing fraction size to 400 cGy while keeping total dose and course duration unchanged, resulted in a 100% loss of focal control within 6 months. Patients considered incurable and irradiated by PMH schedule responded in 83% of courses compared to 51.4% response rate in patients irradiated with other schedules (except) modified PMH regimen). Other aspects of melanoma management are analyzed. (author) 12 tabs., 3 figs., 32 refs