BACKGROUND: Side airbags (SABs) were developed as an energy-absorbing barrier to protect specific occupant body regions in near side impact motor vehicle collisions. METHODS: The National Automotive Sampling System Crashworthiness Data System was used to evaluate drivers and front-seated passengers in 1998 or newer vehicles involved in near side impact collisions. Risk ratios were calculated comparing the risk of head and thoracic injury among occupants in vehicles with and without SABs adjusting for occupant, vehicle, and collision characteristics. RESULTS: Occupants in vehicles equipped with head protection SABs had a 75% lower risk of head injury (p = 0.008) after near side collisions. With respect to thoracic injury, SABs that provide thoracic protection are associated with a 68% reduction (p = 0.01) in thoracic injury risk. CONCLUSION: As SAB-equipped vehicles become an increasingly larger segment of the on-road vehicle fleet, the impact of head and thoracic injury after near side impact collision is likely to be reduced.