In order to elucidate a large north-south difference in salt intake of Japanese, salt metabolism and preference among dormitory students at Jichi Medical School, who come from different parts of Japan (2-3 per prefecture), were analyzed. In the cafeteria, the students chose their own dishes in accordance with their preference, and the salt contents of the three meals were analyzed by Na-electrode. On the other hand, 24 hour urine of each student was collected and analyzed. At the same time salt preference data were collected. Experiments were repeated in 1978 and 1979: Japan, average Southern areas Northern areas(1978) Urine Na+ 188.2±65.9 178.3±63.4 202.9±60.6 (mEq/24hr) Urine Cl- 179.6±55.6 172.4±54.3 189.8±53.9 (mEq/24hr) Diet Na+ 187.5±92.2 170.5±88.6 218.8±94.9 (mEq/24hr) These small differences observed in 1978 (102 students) were also found in 1979 (106 students), while there were no significant differences in urinary K+ (43.9±14.4mEq/24hr), creatinine (1435±363mg/24hr), urea N (7.01±1.79g/24hr), body weight (61.9±7.2kg), height (169.92±5.36cm), blood pressure (122.3±11.4/75.9±8.0) and creatinine coefficient (23.25±2.58mg/24hr/kg, male). As the cause of these differences there was an extreme difference in salt preference between south-and north-originated students (χ2 was 6.77 in 1978, and 11.6 in 1979). These differences were plotted on the map of Japan. Although the salt intake of Japanese is still very high, the extremely high intake in northern Japanese will decrease because of westernized eating habits among young people and the change in life styles.