The trends in the incidence of various morphological types of cutaneous malignant melanoma (CMM) in the Swiss Cancer Registries of Vaud and Neuchatel (total population 786 000 in 2000) were analysed over the period 1978-2002. Overall, the age-standardized (world) incidence of CMM increased from 5.7/100 000 to 16.8/100 000 for men (+195%) and from 7.9/100 000 to 18.7/100 000 for women (+137%). However, there was no consistent trend for nodular melanoma and other or unspecified morphological types, and the upward trends were observed for lentigo maligna melanoma (from 0.2/100 000 to 1.5/100 000 for men and from 0.5/100 000 to 2.1/100 000 for women) and mainly superficial spreading melanoma [from 2.5/100 000 to 10.2/100 000 for men (+308%) and from 3.3/100 000 to 12.3/100 000 for women (+273%)]. This has implications for aetiology, as the various morphological types of CMM may have different determinants, and for prevention, as the rise in superficial spreading melanomas, which are comparatively thin, may explain the increased survival rates registered for CMM over the last three decades. [Authors]