A total of 14 epidemiologic studies from four countries, involving 2,786 workers is reviewed for respiratory symptoms, pulmonary function, antibodies to swine house allergens, and exposure-response variables. Cough and phlegm were the most common symptoms (ranging from 12 to 55%). Tightness of chest and wheezing were frequently reported (12 to 33%) as well as episodes of organic dust toxic syndrome. Acute symptoms, directly associated with work, were from 1.5 to 2 times more prevalent than chronic symptoms. Baseline pulmonary function generally revealed decrements in flow rates, but not volumes; over-shift changes showed small decrements in both flows and volumes. IgG antibodies to swine house antigens were common; no relation to symptoms could be found. Exposure response studies were limited, but relationships were seen between endotoxin and pulmonary function decrements, or respiratory symptoms.