3,258 randomly selected adult household residents of Edmonton were interviewed by trained lay interviewers using the Diagnostic Interview Schedule (DIS). Lifetime prevalence for 16 DIS/DSM III diagnoses are given. Overall 33.8% of the population had one or more diagnoses and, excluding substance use disorders, one fifth of the population had a diagnosis. The most common lifetime diagnosis was alcohol abuse/dependence, followed by phobia and major depressive episode. Men were more likely to have had substance use disorders and antisocial personality disorder and women more likely to have had major depressive episode, dysthymia, agoraphobia and simple phobia. Those who were married had generally lower lifetime prevalences. Those over age 65 had the lowest prevalence of any age groups.