OBJECTIVES:To determine whether previously reported high mortality rates associated with bilateral femoral fractures have decreased over time. DESIGN:Retrospective review. SETTING:Urban academic trauma center. PATIENTS: STUDY GROUP:54 adults with bilateral femoral fractures treated at our center from 2000 to 2006. The 108 fractures were initially treated with external fixation (11%), reamed antegrade nailing (23%), and reamed retrograde nailing (67%). Unilateral control group: 461 patients with unilateral femoral fractures treated at our center from 2002 to 2005. INTERVENTION:Univariate analysis compared our results with those of a published historical control group from the same center approximately 15 years ago (study period, 1984-1990). MAIN OUTCOME MEASUREMENTS:Mortality rates. RESULTS:We noted marked differences between the current mortality rate associated with bilateral femoral fractures and that of the historical control group. The mortality rate decreased over time at our center for both bilateral (26%-7%, P = 0.002) and unilateral (12%-2%, P = 0.0001) fractures. Mortality rates were still significantly higher (P = 0.037) for bilateral (7%) than for unilateral (2%) fractures. CONCLUSIONS:Mortality rates and Injury Severity Scores were reduced for bilateral and unilateral femoral fractures compared with data reported 15 years ago from the same center. The improved outcome might be related in part to changes in resuscitation, triage, intensive care, and orthopaedic management of the patients. However, considering that the Injury Severity Score also significantly decreased, the improvement might have occurred because of changes in injury patterns, perhaps secondary to improved safety features in motor vehicles. LEVEL OF EVIDENCE:Prognostic level III. See instructions for authors for a complete description of levels of evidence.