Factors associated with decisions to enter careers in clinical research were studied based on surveys completed by successful clinical investigators. Three aspects of career decision-making were explored: the timing of the decision to enter a research career, the relationship between research success and the timing of the decision, and the impact of two disincentives to enter research careers (the payback provisions of the national research service awards and the abolition of the physician draft that decreased the attractiveness of research training as an alternative). Survey results document the importance of medical school experiences in career decisions. Further, the correlation between the time of career decision and research success supports arguments for early research experiences upon which decisions can be made. Disincentives for entering a research career were not seen as barriers that would have prevented the majority of respondents from entering a research career. The results of the study led to a strong recommendation that research opportunities for medical students be enhanced as one mechanism for positively influencing decisions in favor of research careers.