The purposes of this study were to define the attitude of mature aging and to examine the relationship between the mature aging attitude, successful aging, and psychosocial maturation. For these purposes, we conducted two different studies with 719 and 350 adults over 60 years of age. The findings were as follows: First, participants with higher mature aging attitudes reported better activities of daily living(ADL) and instrumental activities of daily living(IADL), less disease, more social activity, and better psychosocial well-being. Second, there were no age or gender differences shown in mature aging attitudes and psychosocial maturation; however, ego identity differed according to education, health status, and economic status. Furthermore, participants with higher mature-aging attitudes reported higher wisdom, ego integrity, and gero-transcendence than those with lower mature-aging attitudes. These results were discussed in terms of the effectiveness of the mature aging concept in the well-aging model for Korean elderly.