Successful aging (Rowe & Kahn, 1997) is conditioned by aspiration to be active and by the ability to maintain social relations. Activity improves the emotional lives of seniors and is associated with a reduction of some symptoms of aging. Our study verifies if the number of activities (informal and solitary) is associated with quality of life and whether subjective age may be a mediator of this relationship. The 136 seniors above 60 were tested by our authorial scale of activity and the WHOQOL-BRIEF. The results showed that older persons’ higher quality of life levels are related not only to the number of activities undertaken, but also to the frequency that these activities are engaged in. The mediating role of subjective age in relation to one’s activities and quality of life was also indicated, which, concerning general quality of life, turned out to be a cooperative suppression.