Group-based exercise programs have been shown to be one means of not only increasing activity levels for older adults but sustaining physical activity. However, research has shown that only a small proportion of older Manitobans participate in exercise classes. There are several factors that could affect attendance and adherence to group-based exercise programs amongst older adults which are 1) person-level factors including current/previous physical activity levels, educational attainment, health status, and personal motivators, 2) instructors’ characteristics including personality, professionalism and previous experience, 3) program design including location, affordability and variety of exercise classes and 4) social interaction. In this study, we focused on factors that are related to exercise programs and instructors, which are instructors’ characteristics, program design and social interaction in accordance with the purposes of our study.