T his issue reviews the clinical trial data for asenapine, one of the two recently approved antipsychotics in the United States. A subsequent issue will report on iloperidone. Asenapine is the latest agent to receive FDA approval for both the acute treatment of schizophrenia and manic or mixed episodes associated with bipolar I disorder in adults. It is marketed in the United States under the trade name Saphris (Schering Corp.) and is administered sublingually (SL). The recommended starting and target dose for schizophrenia is 5 mg twice daily, and the recommended starting dose for bipolar I disorder is 10 mg twice daily. The safety of asenapine at doses greater than 10 mg SL BID has not been assessed in clinical trials. This review will consider asenapine's neuroreceptor profile, the data to support its utility in managing various symptoms associated with these disorders, and how asenapine may distinguish itself from other agents in its class.