The purpose of this study was to examine the nutritional effect on calcium stone disease in Japan following World War II and secondly to investigate the relationship between urinary electrolyte excretion and dietary intake clinically. The following results were obtained. 1) tone disease and nutritional environment: Renal stone disease in the late 1970's increased by about three times than that of the 1940's. Fats and oils, animal protein and calcium intake increased emarkably after the World War II and consumption of milk plus milk products, meat and animal products also increased remarkably compared with 1950's values. 2) Calcium stone former and dietary habbits: A survey of the diet was made in approximately 140 male calcium stone formers, ranging from 20 to 59 years of age, (41.6±0.9: Mean±Standard Error) for periods of successive five days to two weeks. The results were compared with the data of healthy Japanese resulting from the National Nutrition Survey (1980) and the Recommended Allowance for Daily Nutrients Requirement (1975-1985) in Japanese (recommended by the Japanese Ministry of Health and Welfare). The ingested amount of calcium was unexpectedly small (432 mg/day) and did not reach the level of the allowance (600 mg/day). It was found that the ingested magnesium in stone formers was very small because the insufficient ingestion of vegetable. The ratio of milk and milk products to the ingested amount of calcium was under twenty-five per cent and under 200 mg/day in most cases. 3) Diet and urinary electrolyte excretion: A comparative study of urinary electrolyte excretion and the ingested nutriment on the same day was made. The ingested amount of total protein correlated with urinary calcium excretion ( p <0.01) and had the highest coefficient of determination to the urinary calcium excretion by multiple regression analysis. From these results we have concluded that the individual dietary guidance fitted to individual dietary habits should be the primary measure for the prophylaxis of renal stone disease.