Social phobia (social anxiety disorder) is a common disorder that is receiving more attention as new treatments become available. Little is known about social phobia as it appears in the primary care setting. The purpose of our study was to determine the prevalence of social phobia in a primary care clinic, the rates of comorbidity with other anxiety and mood disorders, the extent of disability, and patterns of healthcare utilization.A total of 511 English-speaking adults presenting for routine medical care participated in a 2-stage screening consisting of the administration of a self-report measure for social phobia followed by a structured diagnostic interview. We determined current (1-month) prevalence of social phobia, current comorbid disorders, and we ascertained use of health care in the previous 6 months. We also administered brief functional impairment and disability indices.A lower-bound estimate of 7.0% of primary care attendees suffered from social phobia as defined in the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition. Comorbidity with major depression (58.3% of cases of social phobia) was extensive, somewhat less so with panic disorder (27.8%) and generalized anxiety disorder (30.6%). Social phobics reported significantly more impairment in all functional domains than primary care patients without mental disorders; this was most pronounced in patients with the generalized subtype of social phobia. Social phobics made greater use of health care resources than patients who were not mentally ill, yet few (20%) were receiving appropriate psychotropic medications.Patients with social phobia frequently present to primary care medical settings, and manifest impairment in multiple functional domains. But, on the basis of the low rate of psychotropic prescription, it seems that social phobia is either undiagnosed or felt by physicians to be unlikely to benefit from such treatments. Social phobia is highly comorbid with major depression and with other anxiety disorders in the primary care setting. Attention by family physicians to the presence of depression or panic attacks should signal the need to query patients about possible social phobia.