Twenty-eight patients with a DSM-III diagnosis of agoraphobia with panic attacks who completed a 4-month combined drug and behavioral treatment program and who were then discharged on imipramine were interviewed 1 to 5 years after being discharged. At the time of follow-up, half of the patients were medication free, eight were receiving a lower dose of imipramine, two were receiving the same dose as at the time of discharge, and four patients were receiving other antipanic medications. Panic attack frequency remained reduced at the time of follow-up, as did all anxiety and all impairment ratings. These improvements were similar between patients receiving and not receiving imipramine at this time. Long-term outcome was independent of nonpharmacological therapy during the follow-up interval and lifetime diagnosis of major depression at the time of admission. Our data suggest that improvement observed after 4 months of treatment with imipramine and behavioral therapy is maintained after 1 to 5 years, even for many patients who reduced the dose of or discontinued imipramine. Long-term, randomized studies are needed to compare the efficacy of treatments and to determine treatment duration.