Sweat electrolytes were initially elevated in a child who was diagnosed as having celiac disease and also in one with psychosocial failure to thrive. Subsequent sweat tests were normal after nutritional status of the patients had improved with therapy. The reports of elevated sweat electrolytes in conditions other than cystic fibrosis are discussed. It is emphasized that sweat test methods other than the quantitative pilocarpine iontophoresis method are not reliable. The occurrence of false-positive sweat tests demonstrates the need for care in the interpretation of elevated sweat electrolytes and the necessity of performing repeat quantitative pilocarpine iontophoresis for the establishment of the diagnosis of CF. Celiac disease and malnutrition from other causes may cause sweat electrolytes to be elevated.