Objective: To examine the effects of early maternal and paternal depression on child expressive language at age 24 months and the role that parent-to-child reading may play in this pathway. Participants and methods: The 9-month and 24-month waves from a national prospective study of children and their families, the Early Childhood Longitudinal Study-Birth Cohort (ECLS-B), provided data on 4,109 two-parent families. Depressive symptoms were measured with a short form of the Center for Epidemiologic Studies Depression Scale (CES-D). Parents reported on positive parent-infant interactions, child expressive vocabulary, and demographic and health information at child age 9 and 24 months. Linear regression was used to estimate associations between depression, parenting, and child vocabulary. Structural equation modeling was used to test the hypothesis that parent reading behavior mediates the parent depression to child vocabulary pathway. These models were adjusted for demographic indicators. Results: As previously reported from this national sample, 14% of mothers and 10% of fathers exhibited elevated levels of depressive symptoms at 9 months. For both mothers and fathers, depression at 9 months was negatively associated with contemporaneous parent-to-child reading. Only for fathers, however, was earlier depression associated with later reading to child and related child expressive vocabulary development. A model describing this pathway demonstrated a significant indirect pathway from depression to vocabulary via parent reading to child. Conclusions: Depression is a significant problem among both mothers and fathers of young children, but has a more marked impact on the father's reading to his child and, subsequently, the child's language development.