Multiple measures of hostility were administered to middle-aged and older volunteers. There was a positive association between age and self-report measures reflecting hostile beliefs about others, including cynicism and suspiciousness. There was a weak inverse relationship between age and self-report measures of the overt expression of anger and aggression, but no association between age and measures of covert hostility was found. There was a positive relationship between age and an assessment of hostile behavior that was based on the respondent's interaction style during an interview. The magnitude of these age trends did not differ between men (n = 50) and women (n = 75). These findings illustrate the multidimensional nature of hostility. They also have practical implications for older people because hostility is associated with psychological well-being and has been shown to have consequences for health and longevity.