A series of interventions (administrative, clinical and educational) was introduced to improve the quality of trauma care at Royal Prince Alfred Hospital, the designated trauma centre for the Central Sydney Area Health Service (CSAHS). A prospective, 'before and after' study was conducted to assess changes in outcome following the introduction of these measures. The trauma centre survival rate for patients admitted with serious injury (Injury Severity Scores > 15) increased significantly, from 72% in the nine months before trauma centre designation to 89% in the nine months after (P = 0.005). The peer review designated, potentially avoidable death rate did not change significantly over the two study periods, remaining in the 20-30% range. Similarly the unexpected death rate (TRISS) did not change significantly, remaining in the 20-45% range. A trend to a lower trauma centre mortality in those arriving with a systolic blood pressure < or = 90 mmHg was noted. Seven out of 14 patients 'at risk' from exsanguination died in the first 9 months compared with one out of seven in the second 9 months (P = 0.17). An unexpected finding was a change in the degree of injury severity and physiological status in patients arriving at the trauma centre. The Injury Severity Scores were significantly lower (P = 0.008) and the Revised Trauma Scores significantly higher (P = 0.0006) in the latter 9 months of the study. It was concluded that the improved trauma centre survival rate was a reflection of a reduced hospital mortality from haemorrhagic shock in conjunction with a lesser degree of injury severity in patients admitted from the CSAHS.