Purpose: Children of parents with bipolar disorder are at an increased risk of developing mood disorders compared to children without bipolar parents. Early signs of bipolar disorder include symptoms of anxiety, depression, and inattention. Pharmacological interventions for treating these symptoms are often poorly tolerated and may accelerate the onset of manic symptoms. Mindfulness-Based Cognitive Therapy-Child (MBCT-C), an evidence-based manualized 12-week group intervention, has been shown to effectively treat mood and anxiety disorders in children/adolescents. However, there has been no examination of MBCT-C for youth at high risk for bipolar disorder. We examined the effects of MBCT-C on outcomes among youth with anxiety disorders and a familial risk for bipolar disorder.Methods: Participants were 10 children/adolescents (Mage=13.17, SD=1.93; 80% girls; 40% White/African-American) who met DSM-IV criteria for an anxiety disorder (i.e., generalized anxiety disorder, separation anxiety disorder, panic disorder or social phobia) and had at least one parent with bipolar I disorder. A within-subjects, pre-post design was used to examine changes in anxiety, mindfulness, and emotion regulation associated with participation in MBCT-C. Results: Significant decreases were seen in both child-rated (Mpre=18.5 vs. Mpost=4.7, t=10.8, p<.01) and clinician-rated anxiety symptoms (Mpre=11.1 vs. Mpost=4.3, t=6.1, p<.01). Additionally, reductions in clinician-rated anxiety symptoms were significantly correlated with improvements in mindfulness (r=−.69, p<.05) and emotion regulation (r=−.82, p<.05). No significant changes were seen pre-post intervention in depressive symptoms, mania symptoms, mindfulness, or emotion regulation - though all changes were in the expected direction. Conclusion: Findings support the preliminary efficacy of MBCT-C in reducing anxiety among youth at risk for bipolar disorder, and suggest that changes in anxiety symptoms may be associated with changes in mindfulness and emotion regulation processes. Further research utilizing an active control group, larger sample size, and objective markers is warranted.