The study objective was to assess whether exposure to sunlamps and sunbeds represents a risk factor for cutaneous malignant melanoma (CMM). A 1-to-1 unmatched case-control study was conducted among subjects 20 years old or more with naturally non-pigmented skin in Germany, France and Belgium. A total of 420 consecutive patients with CMM diagnosed from I January 1991 onward were derived from hospital registers; 447 controls with no history of skin cancer were chosen at random in the same municipality as the cases. Exposure to sunlamps or sunbeds starting before 1960 is associated with a crude estimated risk of CMM of 2.71 (95% CI: 1.06-7.78) for at least 10 hr of accumulated exposure. This risk is of 2.12 (95% CI: 0.84-5.37) after adjustment for age, sex, hair colour and average number of holiday weeks each year in sunny resorts. Subjects who experienced skin-burn due to sunlamps or sunbeds, and who had accumulated at least 10 hr of exposure, displayed a crude estimated CMM risk of 4.47 (95% CI: 1.45-13.7), which rose to 8.97 (95% CI: 2.10-38.6) for those who exposed their skin for tanning purposes. The risk associated with skin-bum is only marginally modified after multiple adjustments for host characteristics and recreational exposure to sunlight. Apparently, sunlamps and sunbeds share the increased risk of CMM, which seems to concentrate in subjects exhibiting hazardous behaviour towards ultraviolet radiation sources. However, although it is reasonable to believe that high doses of pure ultraviolet A radiation can be dangerous, this is not firmly established by this study. Most exposures to ultraviolet A tanning devices began after 1980; therefore, epidemiologic studies have difficulty in revealing any increase in risk of CMM starting after 1980 because of the latent period between exposure and occurrence of melanoma. Public health authorities should have a cautious approach towards the rapidly developing fashion of tanning under sunlamps or sunbeds.