Results are presented of a comprehensive drug study carried out on specimens from drivers and pedestrians fatally injured in Ontario. Toxicological analyses were regularly performed on blood and urine and occasionally on vitreous humor, stomach contents, and liver. The analytical procedures could detect and quantitate a wide variety of drugs including such illicit drugs as Cannabis. With respect to drivers, alcohol was found in 57% of the study sample and drugs other than alcohol, in 26%. However, in only 9.5% of the drivers were psychoactive drugs (other than alcohol) detected in the blood in concentrations that may adversely affect driving skills. Delta-9-Tetrahydrocannabinol and diazepam accounted for a majority of the findings in this category.