Eight workers were monitored by the dermal patch/hand rinse technique for exposure to the fungicide aluminum tris-o-ethyl phosphonate [fosetyl-Al or ALIETTE®] during treatment of ornamentals in a greenhouse, using commercial back-pack sprayers. The mean total dermal exposure for mixers was 512 μg a.i./hr and for applicators 389 μg a.i./hr. Mixers had higher exposure to the face and neck (213 μg/hr) than did applicators (115 μg/hr). Workpants provided 4 to 6 times greater protection than workshirts. The highest exposure for both activities was to the forearms. Hand exposure represented only 6% of total exposure, while regions protected by clothing contributed 47% of total exposure for mixers and 60% for applicators. Respiratory exposure contributed 7–9% of total exposure. The high variability in dermal patch results suggests a lack of precision in the sampling methodology, and indicates a need for larger sample sizes.