The aim of this study was to determine whether bipolar patients who had been stabilized on combined antipsychotic and mood-stabilizer medications and were currently in remission benefited from continuation of the antipsychotic medication. Remitted bipolar patients were randomly assigned to either remain on adjunctive antipsychotic medication or to taper to placebo. Antipsychotic/placebo medication assignment was double-blind. Subjects were outpatients at a university-affiliated community mental health center. Fifteen subjects consented and proceeded with eligibility assessments. Five subjects were never randomized. One of these was excluded when the Structured Clinical Interview for DSM-IV interview revealed schizoaffective disorder. The remaining four subjects were not randomized for other reasons. Three randomized subjects never received study medications, or were withdrawn by the investigator within 1 week after beginning study medications. The seven remaining subjects received study medication for more than 1 week. Five subjects were randomized to taper to placebo and two to antipsychotic continuation. Of the five randomized to taper to placebo, three successfully tapered and completed the year of follow-up in continuous remission. One subject became manic 4 months after taper was completed, and one subject became psychotic, in the absence of a mood episode, during taper. Of the two subjects randomized to double-blind antipsychotic continuation, both completed the year of follow-up in continuous remission. When adjunctive antipsychotic medications are discontinued, bipolar patients' clinical symptoms can remain unchanged. Others are, however, at risk for manic relapse.