Information on exposure and reaction to sunlight, together with the history of exposure to fluorescent lighting, was elicited by postal questionnaire. Case-control analysis from 58 patients with malignant melanoma, 182 matched controls and 151 unmatched controls showed associations between malignant melanoma and (i) bouts of painful sunburn, (ii) reaction of untanned skin to sunlight, and (iii) number of moles (on right forearm), whereas no association could be found with exposure to fluorescent light at work.