This paper describes a Phase I pilot study for the future development and eld testing of a prototype CD-ROM program called the MEMORY WORKOUT. The MEMORY WORKOUT helps older adults increase and monitor changes in their daily physical and cognitive activity levels and these effects on physical functioning and memory. A holistic, multimodal model of memory provides the theoretical base for the design of the program. The primary purpose of this program is to enhance users' appreciation for the immediate and longer term bene ts of exercise and physical activity on daily mental and physical function. Phase I results 241 242 G. W. Rebok and D. J. Plude with 24 older adults (mean age D 71.2 years) indicate signi cant cross-sectional relationships among exercise time, exercise ef cacy, and word list memory, and moderate to strong interest in improving memory and physical activity. Using Phase I prototype information, the goal of a Phase II project is to produce a complete, interactive, multimedia CD-ROM program that includes tness training, assessment, and simulation components that are appropriate for adults over age 60.