Background: Trait and automatic approach-avoidance (AA) tendencies are central concepts in research on affective disorders. We longitudinally examined the associations of trait and automatic AA tendencies with the risk of onset and chronicity of anxiety and depressive disorders. Methods: Participants were subdivided into those with (n = 766) versus without (n = 1,636) a current anxiety or depression diagnosis at baseline. Clinical diagnoses were reassessed after 2-year follow-up. Automatic AA tendencies in reaction to facial expressions were assessed using the Approach-Avoidance Task, whereas self-reported trait AA tendencies were assessed using the Behavioral Inhibition System and the Behavioral Activation System scales. Analyses were adjusted for socio-demographics (basic adjustment) and for severity and history of psychopathology (full adjustment). Results: Stronger trait avoidance tendencies predicted both increased risk of onset and increased risk of a chronic course of anxiety disorders after full adjustment (Odds ratioonset= 1.55, P <.001, and Odds ratiochronicity= 1.31, P =.03). The associations between stronger trait avoidance tendencies and increased risk of onset and chronicity of depressive disorders were no longer significant after full adjustment. In contrast, trait approach tendencies and automatic AA tendencies were not related to onset or chronicity of disorders. Conclusions: Increased trait avoidance tendencies are a risk factor for affective disorders in general, with possibly a slightly more pronounced role in anxiety than depressive disorders. This underlines the importance of addressing trait avoidance tendencies in both the treatment and aftercare of affective disorders.