In an attempt to investigate the pattern of the urinary acidification process in the Korean, the urinary excretion of phosphate, ammonia, and the titratable acid were measured in 20 medical students (A group) and in 15 psychiatric patients (B group) under regular Korean diets, while the effects of high protein diets on them were studied in 4 subjects. In addition, TmPO₄ was also determined in 11 subjects. The urinary excretions of phosphate, titratable acid, and ammonia under regular Korean diets were markedly lower as compared to those of the Europeans. However, there was no difference in the plasma concentration of phosphate between the Korean and the European. Upon administration of high protein diets, the urinary excretions of phosphate and titratable acid increased while the urine pH and the ammonia excretion were little affected. Thus, the correlations between urinary nitrogen and titratable acidity were 0.50 and 0.65, respective1y, showing a linear relationship. However, the correlation between urinary nitrogen and ammonia excretion was slight. The value of TmPO₄ ranged from 74 to 355 µM/min with the mean of 193 µM/min, which is considerably higher than that of the European. On the basis of these findings, the overall pattern of the urinary acidification processes in the Korean is discussed.