This paper reports the results of a study on drug involvement in fatal traffic crashes in the Province of Ontario, conducted jointly by the Traffic Injury Research Foundation of Canada, the Office of the Chief Coroner and the Centre of Forensic Sciences, Province of Ontario. Blood and urine samples were derived from 484 Ontario drivers and pedestrians fatally injured over a one year period. These specimens were screened for a wide range of (at least 90) phychotropic and other drugs. Drugs (other than alcohol) were detected in 26% of the victims. Thirty-four different drugs were detected. Those detected most frequently were cannabinoids, salicylate, diazepam, codeine, acetaminophen and phenobarbital.