In this study, the validity of a model designed to promote the work ability of aging workers was examined. The target areas of work ability promotion were searched for the characteristics that explain work ability the best. In addition, the way work ability relates to the quality of work and retirement was examined. The subjects (n = 1101) participated in the follow-up study on aging Finnish workers in 1992 and 1997. The results consistently supported the model for promoting work ability. All four areas of focus-(i) work demands and the environment; (ii) work organization and the work community; (iii) the promotion of workers' health and functional capacity; and (iv) the promotion of professional competence-proved to be strongly associated with work ability. Good work ability was associated with a high quality of work and the enjoyment of staying in one's job. It also predicted active and meaningful retirement.