This article, part of a recently completed research project on safety belts, presents results on neck injuries. A total of 3927 injured front-seat occupants (drivers and passengers) involved in two-car crashes were studied. Among them, 725 sustained neck sprains (ICD-9 code 847.0); some of them may have sustained other injuries as well. The more serious injuries to the cervical spine were more prevalent among the unbelted occupants. Neck sprains were relatively more numerous among belted occupants compared with unbelted ones, with a relative risk estimate of 1.68. Similar results hold also for subsets of the data on different types of collisions; the relative risks ranged from 1.39 to 2.42. A log linear model was constructed for the odds ratio (neck sprain vs. no neck sprain) taking into account the following factors: (1) seatbelt use, (2) direction of impact, (3) authorized speed limit, and (4) vehicle weight. The resulting relative risk estimate (belted vs. unbelted) became 1.58. The results raise questions about seatbelts and their protection against neck sprains.