Using a cross-sectional survey of potato farm workers in northern Ecuador, we examined the relationship between pesticide exposure and skin disorders. From a farm population census, all pesticide applicators and 1/2 of exposed field workers were selected. Controls were age-matched from urban occupations. Individual exposure measures included overall years and current hours working with pesticides. Farm-level measures included numbers of applications over the last 6 months and an application practices score (range 0-4). Each participant underwent a clinical skin examination, with patch tests to maneb on a sample of dermatitis cases. Exposure-related increases in conjunctivitis (7% of applicators, 0% in other groups), dermatitis (68% of exposed and 55% of applicators versus 31% of controls, p < 0.001) and pigmentation disorders (25% of exposed and applicators vs 10% controls, p = 0.06) were found. Among dermatitis cases (n = 117), 5% were positive to maneb on patch testing. In logistic regression analysis, significant predictors (p < 0.1) of dermatitis included years using fungicides (OR = 1.12 per year) and poor application practices (OR = 1.42 per score unit). Agricultural fungicide application in high-exposure situations can contribute to dermatitis prevalence among farm populations.