Ultrasongraphy is a very useful diagnostic modality for the evaluation of clinically suspicious abdominal masses in infants and children, especially in assessing their existence, size, location, origin and internal consistency. Authors analyzed and present ultrasonographic findings of 92 pathologically and/or clinically proven pediatric abdominal masses that were studied and treated in Chonnam University Hospital during recent 4 year. The results were as follows : 1. The most common origination site was kidney(26 cases : 28.3%), followed by gastrointerstinal tract (21 cases : 22.8%), genital organ (17 cases : 18.5%), non-renal retroperitoneum (13 cases : 18.5%), hepatobilary tract (12 cases : 13.0%), and anterior abdominal wall (3 cases : 3.3%) in order of frequency. 2. The most common mass was hydronephrosis(18 cases : 19.6%). Neuroblastoma (7 cases : 7.6%), hepatoblastoma, ovarian teratoma, periappendiceal abscess and abdominal tuberculosis(6 cases : 6.5%, respectively), W lms tumor (5 cases : 5.4%) were next in order of frequency. 3. The sex distribution is rather similar, that is , male 42(45.7%) and female 50(54.3%) , but characteristically choledochal cyst(2 cases) and genital mass (17 cases) were found only in females. considering age distribution, 78 cases(84.8%) were found within the range of one to 15 years of age. The rest, 14 cases(15, 2%), were under the age of one year. 4. With ultrasonography, the diagnosis of hydronephrosis could be made easily in every cases and we could evaluate its severity and level of obstruction with high accuracy. 5. All Wilms tumor were large, round or oval, sharply marginated and relatively homogeneous solid masses. 6. All neuroblastomas were irregular shaped, poorly defined, heterogeneous solid masses. Tumor calcificaion and extension across the midline were noted in 6 cases (85.7%) and 5 cases(71.4%) respectively. 7. All periappendiceal abscesses had irregular thickened wall and posterior acoustic enhancement 4 cases (66.7%) among them were mixed echo pattern and 2 cases(33.3%) echo free. 8. Among the 6 abdominal tuberculoses, 2 were seen as irregularly defined solid masses, 1 as conglomeration of multiple hypoechoic modulles and 3 as mixed patterns. 9. All hepatoblastomas were seen to be poorly marginated solid masses with more echogenicity than adjacent normal hepatic echo in 5 cases except one. 10. Among the6 ovarian teratomas, 4 cases were cystic and 2 cases solid. Acoustic shadowing was seen in 3 cases. 11. Choledochal cyst (2cases), hydrops of gallbladder(1cases) and cyst of pancreas head (1 cases) had similar ultrasonic appearance as a large elliptical cystic mass, but, it was important in differential diagnosis to ascertain the existence of gallbladder and the connection between the cyst and bile duct.