The Medicare prescription drug benefit (Medicare Part D) is the biggest change to Medicare in decades. Knowledge of the plan among social work undergraduate students and older adults in the community was assessed. Sequential cohorts of students completed a short questionnaire assessing knowledge about Medicare Part D. Among social work students, an increase in knowledge was apparent. Older adults with Medicare knew more about the program than students. For social work students and older adults, Medicare Part D requires extensive learning about a program that is different from all other Medicare benefits, plans, and programs. (Contains 1 table.)