Objective: To examine the prevalence/predictors of mental health (MH) problems and services use in 12- to 36-month-old children who had been investigated for maltreatment. Method: Data came from the second National Survey of Child and Adolescent Well-Being (NSCAW II), a longitudinal study of youth ages 0 to 17.5 years referred to U.S. child welfare agencies. These analyses involved 1117 children 12 to 36 months of age. Sociodemographic, social services, developmental and health data were collected on the children and caregivers. Outcomes were scores over the clinical cutoffs on the Brief Infant Toddler Social and Emotional Assessment (BITSEA) Scales for 12- to 18-month-olds and the Child Behavior Checklist (CBCL) for 19- to 36-month-olds. Results: In all, 34.6% of 12 to 18 month-olds scored high on the Problem Scale of the BITSEA, and 20.9% on the Competence Scale, whereas 10.0% of 19- to 36-month-olds scored over the CBCL clinical cut-off. Children of black ethnicity were less likely to have elevated scores on the BITSEA Problem Scale, whereas children who lived with a never-married caregiver were five times more likely to have elevated scores. Competence problems were associated with prior child welfare history. Elevated CBCL scores were associated with living with a depressed caregiver. Few children with identified MH problems, 2.2%, received an MH service. When we added parenting skills training that might be related to the treatment of child problems, 19.2% received a service. Conclusions: Identifiable MH problems are common, but few children receive services for those problems. The lack of services received by these young, multi-challenged children is a services systems and social policy failure. (Contains 4 tables.)