The association of anthropometric measurements, serum tests, and life-style factors with the risk of clinical gallbladder disease was investigated in a prospective study of 7831 American men of Japanese ancestry in Hawaii. After 152,831 person-years of observation, 471 incident cases of gallbladder disease were diagnosed by histology or radiology. There was an increase in risk of gallbladder disease with a progressive increase in body mass index, height, pack-years of cigarette smoking, and diastolic blood pressure. There was a decrease in risk with an increase in physical activity, after controlling for the effect of other variables. There was also an inverse association with total caloric intake that could be related to dietary restriction in obese subjects or to the limitations of the 24-hr diet history. Serum cholesterol levels and the intake of total fat were not related to clinical gallbladder disease in this cohort.