INTRODUCTION: Bipolar disorder is characterized by recurrent episodes of depression and/or mania along with interepisodic mood symptoms that interfere with psychosocial functioning. Despite periods of symptomatic recovery, many individuals with bipolar disorder continue to experience substantial residual mood symptoms that often lead to the recurrence of mood episodes. AIMS: This study explored whether a new mindfulness-based cognitive therapy (MBCT) for bipolar disorder would increase mindfulness, reduce residual mood symptoms, and increase emotion-regulation abilities, psychological well-being, positive affect, and psychosocial functioning. Following a baseline clinical assessment, 12 individuals with DSM-IV bipolar disorder were treated with 12 group sessions of MBCT. RESULTS: At the end of treatment, as well as at the 3 months follow-up, participants showed increased mindfulness, lower residual depressive mood symptoms, less attentional difficulties, and increased emotion-regulation abilities, psychological well-being, positive affect, and psychosocial functioning. CONCLUSIONS: These findings suggest that treating residual mood symptoms with MBCT may be another avenue to improving mood, emotion regulation, well-being, and functioning in individuals with bipolar disorder.