Purpose. The purpose of this study was to identify characteristics associated with participation in worksite-based health promotion activities. Design. Follow-up interviews were used to identify demographic, attitudinal, and behavioral differences among three employee groups. Reasons employees chose not to participate in health promotion activities were also explored. Setting. All respondents were employed at a large midwestern university and were eligible to participate in free onsite health fairs and health promotion programs. Subjects. A stratified random sample of 89 nonparticipants, health fair participants, and behavior change program participants was interviewed. Measures. The interview was comprised of questions related to demographic information, personal health habits, physical activity, perceived health status, perceived self-efficacy, worksite norms, health promoting lifestyle factors, and knowledge about health promotion activities. Results. ANOVA and chi-squared comparisons revealed few group differences. Graduate students and employees with advanced degrees were most likely to take part in health fairs. Behavior change program participants were older, clerical-technical staff members, and women. Faculty members were least likely to participate. A lack of time was the most often cited reason for nonparticipation. Conclusions. The study was retrospective and the analyses limited due to low statistical power. The results suggest that different groups of employees are attracted to different types of health promotion activities.