PURPOSE: To evaluate the surgical results between fixations by antibiotic-cement loaded intramedullary nailing and antibiotic-cement loaded external monofixator in the treatment of infected nonunion of long bone shaft with mild bone loss and shortening of less than 1 cm. MATERIALS AND METHODS: Among the 15 cases of infected nonunion of long bone shaft, 6 cases treated with fixation by antibiotic-cement coated intramedullary nailing and 3 cases treated with fixation by intramedullary nailing along with antibiotic-cement beads insertion were divided as group I (n=9), and other 6 cases treated with fixation by external monofixator along with antibiotic-cement beads insertion were divided as group II (n=6). There was no difference between the two groups in the degree of infection in the laboratory data and clinical feature and degree of bone loss and shortening. Male was in 7 and 5 patients, average age of the patients was 34.8 (26~53) and 37.2 (20~63) years old and average follow-up period was 15.9 (12~35) and 19.3 (15~41) months in group I and II respectively. RESULTS: Among the nine cases of group I, 3 cases were newly convereted into fixation by antibiotic-cement coated intramedullary nailing at average 9.5 weeks. Radiologic union was gained at the average of 26 weeks from the time of initial nail fixation. Infection was responsive at 6.1 weeks by laboratoey data. Knee ROM of more than 100 degrees was gained in all case and average shortening was 9.2 mm in the last follow-up. And external rotation deformity of more than 5 degrees was noted in 1 case. Among the six cases of group II, radiologic union was gained at 14 weeks in 1 case without converting to internal fixation, and the other 5 cases were converted to antibiotic cement loaded intramedullary nailing at average 12.5 weeks because of delayed uinon or angulation deformity, and radiologic union was gained at average 44 weeks from the time of fixation by external fixator. Infection was responsive at 10.2 weeks by laboratoey data. Knee ROM of more than 100degrees was gained in 5 cases, and average shortening was 11.8 mm in the last follow-up. CONCLUSION: In the treatment of infected nonunion of long bone shaft with mild bone loss and shortening of less than 1 cm, the fixation by intramedullary nailing with the use of antibiotic-cement prefers to the fixation by external monofixator with the use of antibiotic-cement in the velocity of union, control of infection, and in the clinical aspects such as alignment, early ambulation and joint stiffness.