The outcomes of the Virginia Tech mass casualty incident, as evidenced by the low overall regional health system mortality of victims received at 3.8% (1/26) and low critical mortality rate (excluding 1 victim who was DOA) of 20%, coupled with a need to treat a significant amount of moderately injured victims 46% (12/26 with ISS > or = 9) gives credence to the successful response. The successful response occurred as a consequence of regional collaborative planning, training, and exercising, which resulted not only in increased expertise and improved communications but also in essential relationships and a sense of trust forged among all of the responders.