All children enter the world ready to learn and develop; genetics, experiences, cultures, and environments influence these developmental trajectories. Time spent by primary caregivers with children early in life is vital to positive outcomes. Recovery from disruptions in these foundation periods are difficult and time consuming, so it is beneficial to families and communities to consider the variables that cause early disruptions and how they can be reduced. Maternal depression appears to run in families, apparently transmitted through genetic and social factors. The consequences of maternal depression for children may be interference in their typical developmental patterns and increased likelihood of their problem behaviors. Children with problem behaviors interact with children who have typical developmental histories, creating a community concern. Moderators of the link between maternal depression and children's problem behaviors have not been found consistently; one potential moderator is maternal knowledge of child development. Knowledge of child development increases a mother's understanding of developmentally appropriate practices to use with her children. If a depressed mother were knowledgeable about child development, it is possible that the negative influences of her illness on her child would be reduced. The acquisition of greater knowledge may be associated with the mental health of the mother. The goal of this study was to investigate the link between maternal depression and child problem behaviors as moderated by maternal knowledge of child development. The importance of reducing problem behaviors in children with depressed mothers remains central to helping families. The two predictor variables used in this study were maternal depression and maternal knowledge of child development, measured when the child was 14 months and 36 months old. The outcome variable used was child problem behaviors at 36 months. Analyses of variance and LISREL path analyses revealed significant relationships between maternal depression at 14 month and 36 months, between maternal depression at 36 months and children's problem behaviors at 36 months, and between maternal depression at 14 months and knowledge at 36 months. Single mother households were also significantly related to children's problem behaviors. These findings indicate that maternal education programming may not be sufficient to shield children from the deleterious effects of maternal depression. It is also necessary to focus on the mental health of the mother. If decreasing maternal depression when a child is young allows a mother to increase her knowledge of child development, the results for the child could be an increase in appropriate parenting.