Many health promotion interventions have been developed and tested in recent years. Practitioners and researchers must continue to explore how various program delivery modalities can be used effectively and efficiently to optimize program outcomes. A sample of 6,055 participants was drawn from 10 large employers. Participants self-selected into a mail or telephone intervention. This study compared the demographics of those who selected each modality and assessed differences in program success relative to the modalities chosen. Telephone participants were more likely to be older, female, and salaried. Telephone participants were also more ready, confident, and motivated to make a behavior change, when compared to those in the mail program. Researchers found both the telephone and mail programs to be effective in reducing participants' health risk status, though the telephone program was slightly more effective. These findings demonstrate the importance of offering a variety of interventions when promoting healthy changes. More research is needed to investigate the role of participant choice and the combinations of learning experiences that best facilitate sustainable behavior change. (Contains 4 tables.)