OBJECTIVE Compartment syndrome is a devastating complication of tibial fractures. The purpose of this study was to investigate the rate of clinically determined compartment syndrome requiring surgical intervention in tibial fractures by anatomical region and to identify the associated patient and injury factors. METHODS Retrospective cohort. METHODS University level I trauma center. METHODS Acute tibial fractures in 414 patients from January 1, 2004 through October 31, 2006. METHODS Tibial fractures in 414 patients met the inclusion and exclusion criteria. The fractures were classified into 3 groups (proximal, diaphyseal, and distal) based on the anatomic location of the fractures (AO/OTA fractures 41, 42, and 43, respectively). To determine the patient and injury factors associated with the development of compartment syndrome in tibial fractures, the following data were obtained: patient age and sex, mechanism of injury, presence of associated fractures, presence of concomitant head/chest/abdominal/pelvic injury, blood pressure upon admission, open versus closed fracture (Gustilo-Anderson classification if open), status of the fibula, and AO/OTA classification of the tibial fracture. METHODS Rate of clinically determined compartment syndrome requiring fasciotomy by anatomical region of the tibia. RESULTS The rate of compartment syndrome was highest in the diaphyseal group (8.1%, P < 0.05) followed by proximal (1.6%) and distal (1.4%) groups. The diaphyseal group was further analyzed according to patient and injury factors. Patients who developed compartment syndrome were significantly younger (27.5 years +/- 11.7 SD versus 39.0 years +/- 16.7 SD, P = 0.003, Student t test) than those who did not develop compartment syndrome. The mean arterial pressures upon admission of the patients who developed compartment syndrome were also found to be slightly higher (107 versus 98.5 mm Hg, P = 0.039, Student t test) but not significantly so after Bonferroni adjustment. In multivariate regression analysis, decreasing age remained the only statistically significant independent predictor for the development of compartment syndrome (P = 0.006, regression coefficient = -0.0589) in diaphyseal tibial fractures. CONCLUSIONS Tibial fractures of the diaphysis are more frequently associated with development of compartment syndrome than proximal or distal tibial fractures. More specifically, young patients with diaphyseal fractures are at risk for developing this complication and warrant increased vigilance and suspicion for compartment syndrome. A prospective study with sufficient power is needed to further identify risk factors associated with compartment syndrome in tibial fractures.