Reliability of acoustic rhinometry (AR) for preoperative diagnosis and decision of surgery in children with adenoid hypertrophy were investigated in this study. Fifty-five children who cannot tolerate nasal endoscopic examination were included. The AR was performed preoperatively and postoperatively 1 month later. The volume of distance between the 6th and 10th centimeters in rhinogram curve was calculated for evaluating the adenoid notch (AN) region. The volume of AN region was compared with each patient's volume of the adenoid tissue removed with adenoidectomy. Whereas the median adenoid specimen volume was 2.0 (1.0-2.0) cm3 in 23 patients with complaint of nasal obstruction, median AN volumes in the rhinogram curve was 2.3 (0.8-5.2) cm3. All children whose preoperative nasopharyngeal volume was 4.2 cm3 or less had increased volume in the area representing the nasopharynx on rhinogram. We found a statistically significant relationship between the AN and the adenoid specimen volume (P = 0.000, r = 0.797). The sensitivity and specificity were found as 61.2% and 95.8%, respectively. We concluded that the children whose preoperative nasopharyngeal volumes were measured as 4.2 cm3 or less by AR could benefit more from adenoidectomy.