What is the incidence of alcohol and drugs in a sample of seriously injured motor vehicle collision victims, and what differences do we find when we look at use of alcohol and use of other drugs on demographic variables, injury severity measures and crash variables? The sample selected were all motor vehicle collision admissions to the Regional Trauma Unit at Sunnybrook Health Science Centre in Toronto over a 37 month period (N =854). Prospective demographic and injury related information were collected, and motor vehicle collision reports were obtained from the Police forces or the Ministry of Transportation. Blood samples were collected on admission and tested for alcohol