The purpose of this study was to compare accident rates of helicopter emergency medical services (USA-HEMS) to domestic air taxi service (USA-Taxi) and helicopter emergency medical services in the Federal Republic of Germany (FRG-HEMS). Contingency tables compared the total hours flown to the number of fatal and non-fatal accidents for USA-HEMS (1982-7) vs. USA-Taxi (1980-5) and USA-HEMS (1982-7) vs. FRG-HEMS (1982-7). The overall accident rate for USA-HEMS was 11.7/100,000 h, with the fatal accident rate being 4.7/100,000 h. This was significantly different from the USA-Taxi overall accident rate of 6.7/100,000 h and the fatal accident rate of 1.6/100,000 h (chi 2 = 20.441, p = 0.0001). The USA-HEMS overall and fatal accident rates were not significantly different than the FRG-HEMS overall (10.9/100,000 h) and fatal (4.1/100,000 h) accident rate (chi 2 = 0.061, p = 0.97). These data suggest that emergency air transport is inherently more risky than routine air taxi services.