A cost-effective incentive program to increase safety belt use was implemented by the campus police of a large university. For each of the 3-week intervention periods during three consecutive academic quarters, the 22 campus police officers recorded the license plate numbers of vehicles with drivers wearing a shoulder belt. From these numbers, 10 raffle winners were drawn who received gift certificates donated by community merchants. Faculty and staff increased their belt usage markedly as a result of the "Seatbelt Sweepstakes," whereas students increased their belt use only slightly. A cost-effectiveness analysis indicated that the sweepstakes cost an average of $0.98 per each newly buckled driver. During each sweepstakes intervention, officers' belt usage increased significantly, but diminished to initial baseline levels after the final withdrawal of the program. Surveys of officers' opinions indicated that the police would accept the program demands as a regular task requirement. This result and the fact that program promotion and coordination were eventually taken over by two student organizations suggest that institutionalization of the "Seatbelt Sweepstakes" is feasible.