This study examined vigilance in preschool-aged children and explored the relationship between vigilance and unintentional injury. There were 28 participating children, aged 4 and 5 years, who completed a computerized vigilance task for two 5-min sessions. The task generated measures of correct detections, false alarms, reaction time, and the signal detection indices of d' and c. Primary caregivers completed daily injury phone journals for a 4-week period. Results indicated that age and signal probability affected vigilance. Older children made more correct detections, had greater perceptual sensitivity, and performed in patterns similar to adults. Performance was enhanced in the high signal probability condition. In addition, vigilance indicators of perceptual sensitivity and response bias were predictive of injury, while age was not. Specifically, children with lower perceptual sensitivity scores, and who were less responsive to the vigilance task, experienced more unintentional injuries over the course of the study.