Plate fixation is being regarded as one of the reliahle fixation method in the management of tibial fractures. But this technique may leave many complications including infection. However, delayed local infection which developed several weeks after open reduction on the tibia has been rarely described as a complication in the literatures. The purpose of this study is to evaluate the contributing factors to the delayed locaI infection in tibial fracture treated with plate fixation. Authors reviewed and analyzed the 60 cases of tihial fracture that were treated with plate and screws from 1989 to 1996. Analyses dealt with fracture classification, laboratory and radiographic findings and the site of plate application. We defined a delayed local infection as a condition in which patient has infection signs on Jaboratory and physical examination at or over 8 week post-operation without any evidence of osteomyelitis on plain radiographs. We found 7 cases of delayed local infection out of 60 tibial fractures from 8 to 21 weeks postoperatively with an average of 14.1 weeks. All the 7 cases that had been treated with plate on medial aspect of tibia were treated by administration of antibiotics without surgery such as debridement or removal of hardwares. Authors concluded that the medial plating was the most important factor of the development of delayed local infection(Z=1.78).