A study was conducted to compare urinary Ca excretion and factors influencing urinary Ca excretion in 30 young and 62 middle-aged Korean women. Mean daily intake levels of total protein and P were significantly higher in middle-aged women but Ca and animal protein intake levels of the two groups were similar. The average percentage of daily Ca intake from milk and milk products in young women was 45% while in middle-aged women it was about 24% The frequency of milk consumption was inversely correlated with blood pressures of the subjects. Mean 24-hour urinary calcium excretion in young and middle-aged women were 163.7mg and 174.9mg respectively. The difference was not significant. Menopause of the mid-dle-aged women did not affect urinary calcium levels. However the proportion of subjects with more than 250mg of Ca in 24-hour urine tended to be higher in middle-aged group Factors significnatly correlated with urinary Ca excretion of subjects were systolic and diastolic The study verifies the need for more systematic studies on Ca requirements and the interrelation-ship among Ca and na metabolism blood pressures and bone loss in the middle-aged Korean.