This study aimed to develop an estimate of the incidence of all medically-treated injury by level of severity and to broadly describe the epidemiology of injury in the Australian State of Victoria in a given year. Victoria has developed a relatively comprehensive injury surveillance system. Data is currently collected by various agencies on injury deaths, hospitalisations and emergency department attendances. The method used to establish the incidence of both unintentional and intentional injury is described. Incidence figures were directly derived, or estimated from, the available Victorian health sector and Coronial data bases for three level of severity (deaths, hospitalisations and medical treatment only) and for causes of injury, age and gender groups, location of the injury event and activity at the time of injury. In 1993/1994, injuries resulted in at least 1487 deaths, 67,402 persons hospitalised and an estimated 397,160 medically-treated, non-hospitalised injured persons in Victoria. In total, over 466,000 people were injured or 10.5 persons per year for every 100 residents. Males sustain 62% of all injuries yet represent 49.5% of the population. Almost three-quarters of injury fatalities and over 60% of non-fatal injuries occur among males. Young people aged 15-24 years account for 22% of all injuries yet represent only about 16% of the Victorian population. Children (0-14 years) also suffer relatively high injury rates, although mainly less severe, while the elderly are at risk of more severe injuries. The leading cause of injury death in Victoria is suicide, followed by motor vehicle accidents, whereas falls are the leading cause of all non-fatal injury. Most injuries occur in the home (36%), areas of sport and recreation (12.5%) and transport (11.7%). They are mainly associated with leisure activities (33.1%), work (11%) and transportation (10.8%). This study demonstrates a method for the development of comprehensive injury incidence estimates. The results indicate that injuries have a significant impact on the Victorian community, health care system and economy in general. Reliable incidence data are necessary for descriptive epidemiology and provide the basis for quality of life and economic cost studies. Together this information has potential application for evidence-based strategic planning and evaluation in injury research and prevention.