The hospital inpatient costs for the treatment of injury were obtained for Dunedin Hospital for a two-year period using the Resource Utilisation System. These data were used as a basis for estimating national inpatient costs for motor vehicle traffic crashes (MVTCs). The results show that injuries were on average more expensive to treat than non-injuries ($3,115 vs. $2,749 per case). At a mean cost of $5,253 per case, injuries due to MVTCs were the most expensive class of injury event to treat. The average cost of treating a case varied by the class of road user, nature of injury, and severity of injury. Pedestrians were on average, twice as costly to treat as motor vehicle occupants. Costs for treating the late effects of motor vehicle crashes were higher, with a mean cost of $5,695. Internal injuries were on average 4.5 times more expensive to treat than intracranial injuries, the least expensive group of injuries to treat. On average, critical injuries cost 15 times more to treat than minor injuries. The cost of treating pedestrians was disproportionately higher than that for other road users. Nationally pedestrians accounted for 10% of all hospitalised road users, but they contributed 18% of the total cost. Internal injuries had the highest disproportionate cost accounting for 7% of cases and 16% of the costs. Similarly, severe and critical injuries combined accounted for 6% of the national cases but contributed 19% of the national costs. Overall, the leading contribution to the total national cost were made by occupants (43%), lower limb fractures (24%), and moderate injuries (37%).(ABSTRACT TRUNCATED AT 250 WORDS)