Previous studies have indicated that high neuroticism is associated with early mortality. However, recent work suggests that people's level of neuroticism changes over long periods of time. We hypothesized that such changes in trait neuroticism affect mortality risk. Growth-curve parameters (levels and slopes) that quantified the trajectories of neuroticism change over 12 years were used to predict 18-year risk of mortality among 1,663 aging men. Proportional hazards models were used to estimate mortality risk from level and slope parameters, controlling for objective and subjective health, depression, and age. Although a parallel analysis of extraversion showed no significant effects, level and slope of neuroticism interacted in their effect on mortality. Men who had both a high average level of neuroticism and an increasing level of neuroticism over time had much lower survival than men without that combination. These findings suggest that it is not just the level of personality traits, but their direction of change, that is related to mortality.