This study investigated the association of seat belt use with occupant characteristics and the effect of seat belt use on occupant injuries and hospital costs for treatments. Data from the Kansas Trauma Registry were used for the analysis; from these, data related to crash victims who were occupants of motor vehicles were extracted. According to the analysis results, the overall seat belt usage among hospitalized highway crash victims was 43%, significantly lower than the observed Kansas seat belt usage rate. Young hospitalized occupants were less likely to wear seat belts, while older crash victims were reported to have the highest recorded seat belt usage rate. A majority of the hospitalized occupants were males, and their seat belt usage was lower than that of female occupants. Occupants who sustained less severe injuries had a higher seat belt usage rate than severely injured occupants. A univariate analysis showed possible association between seat belt usage and occupant age, gender, and injury severity. The mean hospital charge for an unrestrained occupant was about $68,000, while that value for a restrained occupant was about $51,000. Length of stay in an intensive care unit and the injury severity score were also higher for unrestrained occupants. On the basis of the analysis results, it was confirmed that unrestrained occupants have higher odds of being fatally injured than restrained occupants.