Children who are maltreated are thought to have high rates of developmental problems. The purpose of this study was to examine the occurrence of developmental delays among maltreated children under three years of age, and caseworker recognition of those developmental problems using the National Survey of Child and Adolescent Well-Being (NSCAW). NSCAW provides developmental, parent and caseworker information on a nationally representative sample of maltreated children. This study found that developmental delays occurred in 47 percent of these children, based on assessments conducted for NSCAW. However, caseworkers identified only 23 percent of the children with delayed development. This evidence of high rates of developmental problems, coupled with an indication that these problems are often unrecognized by child welfare workers, suggests more effective mechanisms are needed for identifying and enrolling children who have developmental delays into Part C early intervention services. (Contains 2 tables.)