Bipolar disorder is characterized by depressive and/or manic episodes that interfere with daily functioning. Between 10%-24% of bipolar patients experience a rapid-cycling course, with 4 or more mood episodes occurring per year. Characterized by nonresponse to standard mood stabilizing medications, patients with rapid-cycling bipolar disorder are particularly in need of effective, adjunctive treatments. Adjunctive cognitive-behavioral therapy (CBT) has been shown to improve adherence to medication and reduce relapse rates in patients with bipolar disorder. However, no published trials to date have examined the application of CBT to the treatment of patients with a rapid-cycling course of illness, with only a single case study published in the literature. We recently developed a CBT protocol that addresses the specific needs of bipolar patients with rapid cycling. The present study was designed to investigate outcomes with this CBT protocol. Study participants were 10 patients with rapid-cycling bipolar disorder, 6 of whom completed the study. Completers showed significant decreases in depressive mood, and improvements remained stable during the 2-month follow-up. This suggests that CBT for rapid cycling may have beneficial effects.