Background: Increased medical service utilization in patients with panic disorder has been described in epidemiologic studies, although service use in primary care panic patients relative to other primary care patients is less well characterized. Inadequate recognition of panic has been shown in several primary care studies, although the nature of usual care for panic in this setting has not been well documented. This study aimed to document increased service use in panic patients relative to other primary care patients and to characterize the nature of their usual care for panic and their outcome. Method: Using a waiting room screening questionnaire and follow-up telephone interview with the Composite International Diagnostic Interview, the authors identified a convenience sample of 81 patients with panic disorder (DSM-IV) and a control group of 183 psychiatrically healthy patients in 3 primary care settings on the West Coast and determined psychiatric diagnostic comorbidity, panic characteristics, disability, and medical and mental health service use, including medications. A subsample (N = 41) of panic patients was reinterviewed 4-10 months later to determine the persistence of panic and the adequacy of intervening treatment received using the Harvard/Brown Anxiety Disorders Research Program study criteria for cognitive-behavioral therapy (CBT) and an algorithm developed by the authors for medications. Results: Seventy percent of panic patients had a comorbid psychiatric diagnosis. Patients had more disability in the last month (days missed or cut down activities) (p < .0 1), more utilization of emergency room and medical provider visits (p < .01), and more mental health visits (p < .05). Despite the latter, only 42% received psychotropic medication, 36% psychotherapy, and 64% any treatment. On follow-up, 85% still met diagnostic criteria for panic, and only 22% had received adequate medication (type and/or dose) and 12% adequate (i.e., CBT) psychotherapy. Conclusion: These findings suggest a need for improved treatment interventions for panic disorder in the primary care setting to decrease disability and potentially inappropriate medical service utilization.