Studies in other countries have demonstrated that properly worn seatbelts dramatically reduce the likelihood and seriousness of injuries in motor vehicle accidents. However, in the western region of Mexico, they are very rarely worn, due to the erroneous belief that its use does not protect, and may even harm its wearer. In order to ascertain its benefit or lack of it, we undertook a survey, comparing the degree of severity of lesions sustained, as well as the mortality, between a group of 15 patients who wore seatbelts and another of 35 patients who did not wear them; all patients were treated at the Emergency Room of the Hospital de Especialidades del Centro Médico de Occidente, after suffering car accidents. Among the first group, only one patient required hospitalization and there were no deaths. In the second group, all 35 patients had to be hospitalized, eight had sequelae and nine died. We conclude that seatbelts effectively protect the wearer against death and limit the severity of the injuries suffered during car accidents. We propose that educational campaigns to convince the public as to the benefits of its use should be carried out, and after a reasonable interval its use should be mandated by law.