This study focuses on the health examination programs for 3 year old children from a public health point of view. The methodology, items tested, criteria and follow-up systems of urine examination were evaluated. Results of urine examinations of 8,615 children(male : 4,490, female : 4,125), who had been in the health examination program from 1980 to 1985, were studied in the area of K-ku in Y-city. Moreover a follow-up study was performed to discuss the significance of urine examination as mass screening. In the health examination program for 3 year old children, it is efficient to classify those with a score of more than “one plus” into the high risk group with regard to proteinuria and hematuria. It is possible to reduce the false positive rate by checking first morning urine at re-examination. A bettr information net work system must be established to utilize the results of mass health examinations for three year old children.