Children of sole parents have the worst mortality record of all social groups. Road vehicle related injuries account for a large part of their excess mortality. In this case-control study the association between sole parent status and the risk of child pedestrian injury was examined. Cases (n = 258) were children killed or hospitalized as a result of a pedestrian injury in the Auckland region over a period of 2 years and 2 months. Controls were a random sample of the child population. The children of sole parents were at a significantly increased risk of injury (odds ratio = 1.57; 95% confidence interval (CI) 1.09, 2.27). However, there was a striking difference in the effect of sole parent status according to ethnic group. Among European families, sole parenthood was associated with a greatly increased risk of injury (OR = 3.13; 95%CI 1.84, 5.31), whereas in Pacific Island families sole parenthood was associated with a significant protective effect (OR = 0.40; 95%CI 0.18, 0.89). The protective effect of sole parent status in Pacific Island families may reflect the beneficial effects of the social support provided by extended family networks. Children of sole parents in the context of the nuclear family may be particularly vulnerable.