The relationship between water and electrolyte metabolism, and dietary intake were studied in 45 healthy Buddhist nuns who were vegetarians aged 20-34, and 28 nursing students aged 20-22 who stayed at the dormitory of Kyungpook Medical School in the Fall, 1981. The Buddhist nuns obtained significantly higher carbohydrate and total caloric intakes but significantly lower protein and lipid intakes than the female students. The Buddhist nuns excreted significantly higher urine output(1,697±68 ml/day, p<0. 05) and lower osmolality (616±18 mOsm/kg H2O, p<0.05) than the students (1,505±67 ml/day and 688±36 mOsm/kg H2O$). However, both groups excreted similar amounts of urinary Na+, K+ and total osmolar contents. Free water clearance of the Buddhist nuns was higher(p<0.05) than that of the students but the osmolar clearance was about the same in the two groups. Daily urine output showed good correlation with Na output (r=0.76) and osmolar clearance but not with free water clearance. Both groups showed similar values of plasma concentration of creatinine, daily excretion of creatinine and clearance. Urinary excretion of urea for Buddhist nuns was 6.4 g/day, and was significantly higher than that of the students (5.1g/day).