Background: Mine tailings are metallic wastes which are deposited in the environment due to mining activity. Long-term exposure to these metals is harmful to human health. Objective: To determine if chronic exposure to mine tailings constitutes a risk factor for the development of dermatological diseases in the district of San Mateo de Huanchor (Lima, Peru). Methods: An observational case-control study was carried out in the communities of Mayoc, Daza and Tamboraque (exposed to mine tailings, case group) located in the district of San Mateo de Huanchor, and also in the communities of Choccna and Caruya (not exposed to mine tailings, control group) located in the same district. Out of 230 adults, 121 were exposed and 109 were not exposed to mine tailings and out of 135 children, 71 were exposed and 64 were not exposed to mine tailings. Results: In the adult group, 71% of the exposed cases had some noninfectious dermatological disease while in the nonexposed group the frequency was 34% [P < 0.001; odds ratio (OR) 5.40; 95% confidence interval (CI) 3.02-9.68]. A statistically significant difference between groups was found for arsenical dermatitis, nonpruritic papulovesicular eruption, atopic dermatitis, contact dermatitis, seborrhoeic dermatitis and xerosis. In the paediatric population, 71 exposed and 64 nonexposed children were evaluated. Sixty-nine per cent of the exposed group had some noninfectious dermatological disease vs. 30% in the nonexposed group (P < 0.001; OR 6.00; 95% CI 2.71-13.31). A statistically significant difference between groups was found for xerosis and atopic dermatitis. Conclusion: Chronic exposure to mine tailings represents a risk factor for development of noninfectious dermatological diseases in both adults and children. © 2008 The Authors.