Rigid osteosynthesis in mandibular fractures is fully indicated for treatment of both partially toothed and toothless jaws. It si also used in those injured patients in whom conservative way of treatment by means of intermaxillary fixation proves to be inappropriate. AO system compression plate is appropriate to ensure good stability and strength of osteosynthesis. Due to its specially shaped holes, the plate produces tensile and compressive forces on bone fragments. These forces eliminate undesirable effect of muscles attached to the jaw. The authors used compression plates made by the firm Synthes in sixteen cases of mandibular fracture. Satisfactory results of uncomplicated healing were achieved.