In an ongoing longitudinal study, a Big Five Personality Inventory was completed by 122 men and 126 women at age 33. At age 36, the Brief Mood Introspection Scale, the Meta-Evaluation Scale, and the Meta-Regulation Scale were administered to 140 men and 127 women. The results, based on path analyses, lent support to a hypothesized model, according to which current mood (Negative, Positive, Active, Calm) and mood evaluation (Mood Influence, Typicality and Acceptance, Clarity) mediate the relationship between the Big Five personality traits and emotion regulation strategies (Repair, Dampening, Maintenance). For both sexes, Neuroticism was the most significant trait in terms of emotion regulation. A sex difference emerged: in general, personality traits and mood variables explained emotion regulation more significantly in men. Copyright © 2001 John Wiley & Sons, Ltd.