A random sample of 3258 adult household residents of Edmonton, Alberta, Canada were interviewed by trained lay interviewers using the Diagnostic Interview Schedule (DIS), which gives DSM-III diagnostic data on each individual interviewed. This paper reports results for panic disorder. Panic disorder was found to affect women primarily (female:male morbidity risk 2.2:1). The mean age of onset (first symptom) was 19.3 years for men and 21.5 years for women. Rarely did symptoms first occur after the age of forty. The lifetime prevalence rate was 1.7% for women and 0.8% for men and the lifetime morbidity risk was 3.7% for females and 1.7% for males. All twelve panic symptoms were found to be highly specific for panic disorder. Women complained of more (means = 8.0) symptoms than men (means = 6.0). On average 7.3 symptoms were reported. Those with panic disorder showed increased lifetime prevalence rates for major depressive episode (73.4%), alcohol abuse/dependence (54.2%), drug abuse/dependence (43%) and phobia (44.2%). Altogether, 90.4% of those with panic disorder also met criteria for another DSM-III diagnosis, which was 2.7 times the rate in those who did not have panic disorder.