Objective: Maternal maltreatment history and current parenting stress are associated with parenting difficulties. However, researchers have not investigated the mechanism by which these variables are interlinked. We hypothesized that parenting stress mediates the relation between history of maltreatment and parenting behavior. Methods: We assessed a community sample of 291 mothers as they interacted with their 16-month old infants in the home. Maternal history of maltreatment and parenting stress were assessed via self-report inventory; maternal sensitivity toward the infant was assessed with 2 h of direct behavioral observation. Results: Mothers who reported more maltreatment in childhood were less sensitive with their infants; mothers who reported more current parenting stress were also less sensitive. Parenting stress mediated between maternal maltreatment history and current parental behavior. Conclusions: Findings are consistent with an interpretation of parenting stress as a pathway through which maternal history of maltreatment may be linked to decreased maternal sensitivity. (Contains 2 tables.)