As the proportion of older workers is increasing rapidly, the contribution of aged workers becomes important to firm competitiveness. As job satisfaction is a major determinant of job performance and attitudes, Korean companies should ensure the job satisfaction of aged workers. This study tests the process through which aged workers have positive attitudes toward their jobs. The empirical results of the present study reveal that the satisfaction of human resource development (HRD) program increases job satisfaction of workers at early 50’s, while pay level and usefulness of job skills and competences contribute to job satisfaction of workers at late 50’s. The empirical results suggest that Korean companies categorize aged workers into two groups: lower and higher than mid-fifties; and tailor human resources programs and policies to be consistent with different age categories.