To assess calcium and sodium and urinary excretion of preschool children in Busan and to evaluate the relationship of intakes of food and nutrient with urinary calcium excretion, calcium and sodium food frequencies of 25 common foods affecting intakes of calcium and sodium per week, nutrient intake by 24hr recall and 24hr urinary calcium and sodium excretion were measured with 97 preschool children. The mean calcium intake was 436.11mg and below RDA. The mean sodium intake was 1890.11mg. The mean urinary calcium and sodium excretion were 42.88mg and 735.25mg respectivery. The mean urinary calcium/creatinine ratio was 0.20. The urinary calcium excretion showed positive significant correlations with weight, intake frequency of pizza consumed per week and urinary sodium excretion (p<0.05, p<0.05, p<0.001). The urinary calcium excretion per milligram of creatinine showed positive significant correlations with intake frequencies of pizza and common squid consumed per week(p<0.01, p<0.05) and negative correlation with intake frequencies of pizza and common squid consumed per week(p<0.01, p<0.05) and negative correlation with age(p<0.05). No significant relations were found between urinary calcium and intakes of calcium, protein and phosphorus. Urinary sodium was found to be the most important determinant of urinary calcium excretion. Intake frequency of pizza consumed per week was found to be the most important determinant of urinary calcium excretion per milligram of creatinine. Based on the results, urinary calcium excretion was related to intake frequency of pizza consumed per week and urinary sodium excretion. Low calcium intake and increase of calcium loss in the urine potentiated by sodium intake during growth may reduce peak bone mass. So nutritional education is needed in order to increase calcium intake and decrease sodium intake, especially from food like pizza.