Purpose: This study was designed to examine whether preretirement intervention, through preparation programs conducted by social workers, enhances retirees' healthy retirement transition, self-mastery, and well-being outcomes. Methods: Data were gathered at preprogram, postprogram, and at 6-month follow-up. A total of 84 participants filled out pre- and postprogram questionnaires, of which 66 also completed follow-up assessment. Participants were 1-3 months before retirement at preassessment and 4-8 months after retirement at follow-up. Results: The preretirement program improved participants' appraisal of retirement and created lower and more realistic expectations of postretirement work prospects. While these variables changed in the expected direction between pre- and postprogram assessment, participants' scores at follow-up indicated less self-mastery, greater depressed affect, and less positive feelings regarding retirement. Discussion: The short-term value of retirement programs was supported and revealed the importance of follow-up programs to maintain short-term gains and to address additional long-term developments.