Objective: To determine the frequency of panic attacks and panic disorder inpatients with chronic schizophrenia or schizoaffective disorder. Method: Fifty-three male outpatients meeting Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for chronic schizophrenia or schizoaffective disorder were administered sections of the Structured Clinical Interview for DSM-IV (SCID). If panic attacks were reported, patients were queried about treatment and about onset relative to psychotic symptoms. Results: Forty-nine patients were sufficiently organized to participate in the evaluation. Twenty-one (43%) experienced panic attacks, and 16 (33%) had current or past panic disorder. Eight (50%) of the 16 with panic disorder had been treated for panic. Substance dependence was not associated with having panic attacks or current or past panic disorder. Patients with paranoid schizophrenia were more likely than patients with schizoaffective or undifferentiated schizophrenia to have experienced panic attacks (57% versus 20%, %2 = 6.0, P < 0.02) or panic disorder (47% versus 10%, χ2 = 6.9, P < 0.01). Conclusion: Panic attacks and panic disorder are common in men with schizophrenia or schizoaffective disorder. Panic disorder may be an overlooked comorbid diagnosis in patients with schizophrenia.