Painters are exposed to a range of complex chemical mixtures which include organic solvents and dye products with known carcinogenic and mutagenic potential. Trade painters or those manufacturing paints and coatings have increased rates of non-malignant diseases and cancers; including lung cancer, acute leukaemia, bladder cancer, and cancers of the oesophagus, larynx, biliary system, liver, skin, and large bowel. A series of case-control studies of painters, based on the New Zealand Cancer Registry, are presented. These concerned 19,904 male patients registered for the period 1980-4 who were aged 20 or older at the time of registration. For each cancer site studied, the registrants for all other cancer sites formed the control group. Three cancer sites were associated with work as a painter--namely, bladder tumours (odds ratio (OR) 1.52, 95% confidence interval (95% CI) 1.00-2.31), kidney and other urothelial tumours (OR 1.45, 95% CI 0.85-2.50), and multiple myeloma (OR 1.95, 95%, CI 1.05-3.65). Risks for multiple myeloma were greater among car or spray painters and signwriters (OR 2.81) compared with construction and general painters (OR 1.80). No increased risk was found for leukaemia or for respiratory, biliary, skin, or gastrointestinal cancers.