Cross-sectional age differences and longitudinal change were examined on psychological well-being, positive affect, and negative affect, as measured by the Bradburn Affect Balance Scale. Data were collected from 1,159 participants in 1971 and 1985. Cross-sectional analyses showed age differences: older cohorts reported greater overall well-being but lower levels of both positive and negative affect when compared to younger respondents. Longitudinal analyses indicated small but significant changes toward decreased positive and negative affect but increased overall well-being. Negative affect had the strongest effect size. Positive and negative affect showed different patterns of change for different age groups. Taken together, cross-sectional and longitudinal findings suggest that change in affect variables is age-related, although these changes are relatively small. More evident was a pattern of correlational stability with age. Finally, the pattern of the results supports a two-factor theory of psychological well-being.