BACKGROUND : Although injury patterns after motor vehicle crashes (MVCs) are well documented, association between adequate restraint and injury severity is unclear. We aimed to determine if improper restraint affects injury rates and severity. METHODS : A retrospective chart review of 477 children hospitalized in Pediatric Trauma Center after MVC was performed. Injuries in various age groups (0-7, 8-12, 13-16, 17-18 years) with different restraint quality measures (proper [PR] and improper/unrestrained [IUR]) as well as injury severity score (ISS: mild [1-9], moderate [10-15], severe [16-25], and profound [>25]) were evaluated and compared. Chi-square and Wilcoxon rank-sum tests were used for statistics. RESULTS : In all age groups head/neck injuries were most common (55-63%), while abdominal and pelvic injuries were least likely except group 8-12 years where abdominal injuries ranked third (17.1%). Overall, 64.5% had PR and 35.5% IUR. Interestingly, that greatest proportion of IUR was in the youngest age group (0-7). It decreased with aging and children aged 17-18 years were significantly less likely to be IUR compared to those 0-7 years (OR[odds ratio] = 0.58; 95%CI[confidence interval] 0.35-0.94). We did not find significant differences in rates of various injuries between PR and IUR. However, ISS severity in IUR was significantly greater than in PR (median with interquartile range 6(2-14) and 5(1-9), respectively; P = 0.001). As a result, IUR compared to PR were less likely to have mild ISS (OR = 0.6, 95%CI 0.39-0.90) but more likely to have profound ISS (OR = 3.3, 95%CI 1.48-7.43). CONCLUSIONS : Restraint quality has significant impact on injury severity in children after MVC. METHODS : Level III.