Studies suggest altered affect regulation manifested by affective lability in manic/mixed and euthymic states in patients with bipolar disorder (BD). Altered affect regulation may arise from disturbances in interactions between the cognitive and the emotional brain networks. However, the relationship between affective lability and executive function has not previously been studied. Our aim was to investigate affective lability, as measured with the Affective Lability Scale (ALS) in patients with BD (N=32) compared to healthy controls (HC) (N=60), and its relationship to executive functioning. We found significantly higher ALS scores in the BD than in the HC group, indicating a higher degree of affective lability in patients with BD. Sub-sample analysis revealed a significant positive relationship between affective lability and semantic set shifting abilities in BD only. These findings suggest that higher levels of affective lability compared with controls are a trait as well as state dependent in BD, and that disturbed affective lability may arise from an aberrant interaction between cognitive and emotional brain networks.