This study investigates when people prefer to retire, and how their preferences change as they grow older. Subjects were 547 workers and 371 retirees. Information was collected during interviews in 1964 and in 1974. Data were analyzed in a split-plot analysis of variance model. Results indicate the following: (1) an overall shift to later preferred ages of retirement (PAR); (2) the shift in PAR varied significantly depending on whether persons retired during the decade between interviews; (3) those who continued to work demonstrated a greater shift to later PAR; and (4) among those who continued to work, older age cohorts showed a greater amount of change toward later PAR than did younger cohorts. In conclusion, individuals' attitudes toward retirement seem to represent a complex interplay of situational and attitudinal factors. Further research is needed in this area. (Author/JLL)