Positive psychology has recently developed a classification of human strengths (Peterson & Seligman, in press). We aimed to evaluate these strengths by investigating the strengths and life satisfaction in three adult samples recruited from the community (young adult, middle-aged, and older adult), as well as in the surviving men of the Grant study of Harvard graduates. In general, older adults had higher levels of interpersonal and self-regulatory strengths, whereas younger adults reported higher levels of strengths related to exploring the world. Grant study men tended to report lower strength levels than older adults from the community. Among the young adults, only hope significantly predicted life satisfaction, whereas among the middle-aged individuals, the capacity for loving relationships was the only predictor. Among community-dwelling older adults, hope, citizenship, and loving relationships all positively and uniquely predicted life satisfaction, compared with loving relationships and appreciation of beauty in the Grant sample. The following are appended: (1) Comparison of Lists of 16-Strengths and 24-Strengths; and (2) Items Used to Measure Strengths. (Contains 2 figures and 4 tables.)