Acute suppurative arthritis in neonates is very difficult to diagnose early since it does not show typical clinical picture and as a results, delayed diagnosis and improper treatment often leads to permanent disability in patient. To prevent the sequelae follwing acute suppurative arthritis, early surgical treatment and administration of antibiotics are essential. We analysed 15 affected joints in 11 neonates less than 1 month old who were treated by surgical treatment and administration antibiotics. The results were as follows. 1) As for the specific joint involved, those affecting hip joint were most frequent(8 joint: 53%), followed by knee joint(5 joints: 33%) and shoulder(2 joints: 14%). Acute osteomyelitis was simultaneously occurred in 10 joints(67%). 2) As for clinical symptoms and signs, 10 cases (91%) showed limited range of motion with the clinical symptoms and signs similar to neonatal sepsis. 3) As for the causative organism, Gram-negative bacilli was the most frequent one(40%), followed by Staphylococcus aureus(27%) and candida albicans. No organisms were identifiable in four joints(27%). 4) As for the sensitivity test to antibiotics, group of staphylococcus aureus was found sensitive to newer cephalosporins while those of gram-negative bacilli to amikacin in 83%. 5) Average time between the first clinical symptom and operation was 5.14days. 6) The hip joint had yielded most complications(5 cases) followed by knee and shoulder joint, one for each. The accompanying osteomyelitis and delayed treatment were contributing factors to complications.