Transient synovitis of hip joint is a fairly common cause of painful hip in children, which used to be subsided in short time by bed rest and medication. The disease is of interest clinically, not because it is a disabling condition, but because of the difficulties encountered in differentiating it from other more serious diseases of hip joint. Among 79 cases, which were admitted at the Korea University Guro Hospital under the diagnosis of transient synovitis of hip joint since September, 1983, fourty-six cases were followed up for more than 1 year. A clinical analysis upon these cases was made and could be summarized as follows:l. Among the 46 patients, 29 cases(63%) were male and 17 cases(37% ) were female. The most prevalent age was 6 years(10 cases, 21.7%). 2. About half of them were found to have been preceded by presumably predisposing factors such as URI and mild trauma, 3. Pain and limitation of motion of hip joint were presenting symptoms in most of the cases. Radiological abnormalities of soft tissue shadow were noted in 34 cases(73.9%) and among them the gluteal sign(60.7% ) was more prominent than others. 4. Bone scanning with 99m Tc was performed in all cases and increased uptake was observed in 12 cases(26.1%). The ESR was increased in 16 cases(34.8%), but leukocytosis more than 12,000 cells/mm3 was observed in 3 cases(6.5%) only. 5. They were all treated conservatively including traction on bed and NSAID. The symptom duration was less than 7 days in 23 cases(50% ) and average admission period was 6 days. 6. Two cases turned out to be of other diagnosis afterwards than transient synovitis, one of Legg- Perthes disease and the other of rheumatic fever.