To examine the relation between perinatal depression at child age 1 year and behavioral issues and altered social functioning at school age. The Future of Families (formerly Fragile Families) and Child Wellbeing Study longitudinal cohort age 9 nationally representative urban sample was used to examine associations between maternal depression at child age 1 and child behavior and social functioning at age 9 (n = 2,305 children and their mothers). Measures included the Composite International Diagnostics Interview (depression), Child Behavior Checklist total score (child behavior problems) and social function subscale. Clinical significance of child behavior problems and social function problems were determined by normed T-scores. Analyses included chi square, t-tests, and linear regression using SAS 9.4 Survey procedures. Higher household income was associated with lower behavior problem scores (F = 8.76, p < 0.0001, R2 = 0.07. School-aged children whose mothers had major depression at child age 1 (10.8%) were more than twice as likely to have clinically significant behavior problems (OR 2.46, p < 0.0001) than children whose mothers did not have depression (4.1%). Further, children with depressed mothers were more than twice as likely to have clinically significant social function problems than children whose mothers were not depressed (OR = 2.09, p < 0.0001). Children whose mothers were depressed at child age 1 have higher risk of having behavior problems and poor social functioning at age 9. Early and repeated maternal depression screening is needed to treat the disease sooner and attempt to avoid these outcomes.