BACKGROUND Animals secrete allergens into the environment and exposure to these in the workplace may cause sensitization. AIMS To identify the frequency of animal allergen sensitization and symptoms in animal workers. METHODS Using skin prick tests (SPT), we assessed sensitization to 15 mammal and bird allergens in animal workers and controls. We also recorded symptoms and pulmonary function tests. RESULTS There were 100 animal workers and 50 controls included in the study. Thirty-six per cent of animal workers and 10% of controls had positive SPT (P < 0.001, odds ratio [OR] = 5.1, 95% CI 1.7-16.0). The most common sensitizations were to horse (16% in animal workers versus 0% in controls, P < 0.01), canary (16% in animal workers versus 2% in controls, P < 0.05, OR = 9.3, 95% CI 1.2-194), cattle (13% in animal workers versus 0% in controls, P < 0.05), cat (12% in animal workers versus 6% in controls, not significant), rabbit and hamster (10% each in animal workers versus 0% in controls, P < 0.05). Allergy symptoms were reported by 52 animal workers, but only 36 of them had positive SPT. Twelve animal workers had abnormal pulmonary function tests and six had positive SPT. CONCLUSIONS Animal workers are at high risk of occupational sensitization to animal allergens. Exposure should be minimized through control measures and worker education about the risks of exposure and sensitization.