One factor that has been proposed as affecting accidental death rates is the availability of a lethal agent in the environment. The present study explores this hypothesis for the case of firearm availability and the accidental death rate from firearms. Data from Canada indicated that the passage of Canada’s Criminal Law Amendment Act of 1977 (Bill C-51), enforced from 1978 on, was followed by a lower accidental death rate from firearms, but the preventive effect was more clear for females than for males.