"Substance abuse" as used in this chapter refers to the abuse of legal drugs (e.g., alcohol, prescription drugs, over-the-counter drugs) as well as the use of illegal drugs (including cocaine, heroin, marijuana, and methamphetamines). Recognition of the significant role that substance abuse has in CM is increasing, as evidenced by the emerging body of research that links substance abuse and CM. Numerous studies show that substance-abusing parents are at increased risk for abusing and neglecting their children, although the strength of the association varies as a result of methodological differences in the research. Substance abuse has been found to be a major factor in the recurrence of CM, and parental substance abuse has been linked to fatalities from CM. Research published to date on substance abuse as a risk factor for CM has focused almost exclusively on caregivers who were currently active substance abusers. Several studies, however, found that past as well as current parental substance abuse increased the risk of child abuse. Research has also shown that a childhood history of maltreatment dramatically increases the risk that the victim will become a substance abuser. Several mechanisms by which alcohol and drug abuse have been hypothesized to undermine parenting and increase the risk of CM are proposed by Ammerman et al. Substance abuse may contribute to low frustration tolerance and increased anger reactivity secondary to the acute effects of alcohol and other drugs or to the physical withdrawal symptoms associated with substance dependence. Substance abuse may also cause disinhibition of aggressive impulses and may interfere with parenting judgment. Further, drug addiction may cause parents to focus on acquisition and use of drugs instead of meeting the child's basic needs. The author also discuses the effects of prenatal exposure to drugs used by the pregnant mother, as well as postnatal drug exposure. One section of this chapter considers the impact of parental substance abuse on kinship care, since many children of substance-abusing parents are placed in the homes of grandparents. Studies have shown, however, that the health status of such grandparents is often compromised by having to raise grandchildren under such circumstances, with advanced age playing a role in many instances. The chapter advises that increased access to substance abuse treatment is critical in dealing with parental substance abuse and its impact on children. A major challenge in policy and practice relates to permanency planning. Further, drug prevention efforts should target those children who come from homes where parental substance abuse has occurred. Suggestions are offered for future research. 69 references