OBJECTIVE The present study was planned in order to evaluate: (1) the reference value of Japanese school children at a certain grade, (2) the relationship between subjective sensation of nasal obstruction and acoustic rhinometry, and (3) relationship of acoustic rhinometry with gender and body status. METHODS Seventy-five school children in the second grade, which include 39 girls (52%) and 36 boys (48%), ranging in age from 7 to 8 were studied in July 2006. RESULTS The normal mean values of the minimal cross-sectional area and nasal volume were 0.389 and 2.63cm(3) in this group, respectively. In those with nasal obstruction sensation, the cross-sectional areas at the third and the fourth notches were significantly smaller than those without nasal obstruction sensation (p<0.05). Nasal volume weakly correlated to body weight and body mass index. The distance from the nostril to the i-notch was significantly higher in the girls than in the boys (p<0.01). The area at the i-notch was significantly higher in the boys than in the girls. Height, weight, body mass were significantly higher in the boys than in the girls (p<0.01). CONCLUSIONS Acoustic rhinometry is a useful method for evaluation of nasal patency in school children.