This paper describes the analysis of injury-related linked hospital morbidity data by admissions and by individual patients in Western Australia (WA) from 1990 to 1994. Over this five-year period, there were an average of 35,385 admissions and 30,524 people admitted each year for injuries in WA. The age-standardised rates for injury-related hospital admissions and persons admitted for injuries increased significantly, by 2.4% and 1.5% per year respectively, over the five-year period. The number of admissions and the number of persons admitted peaked in the 20-24 years age group but the highest rates were among those aged 75 years and above. Injuries accounted for nearly 10% of all hospital bed day costs and cost about $50 per head of population per year. The cost of hospitalisation rose steadily from $85.2 million in 1990 to $113.6 million in 1994, the average cost being nearly $100 million per year. The average cost per injury related hospital episode was $2,748. Generally, the cost per hospital episode was higher for males and increased with age, following a similar pattern to that for the average length of stay.