Government-operated trauma facilities fill an important role as safety nets in our health system, providing care to millions of individuals who lack health insurance. Because these hospitals are often the most financially constrained, continuous improvement in operating efficiency seems to be a necessary component of their organizational strategy. In this study, we analyze the longitudinal changes in efficiency of a large sample of government-operated safety-net hospitals from 2004 to 2008. Employing an analytical tool called data envelopment analysis, our findings suggest that as a group these hospitals have become more efficient over time, improving by 2.1 percent over the five-year study period.