The developmental assessment of infants and toddlers in Early Head Start (EHS) programs is a continuous process throughout the entire length of the child's enrollment in the program. This technical assistance paper will define the concepts of screening, ongoing assessment, and in-depth evaluation; discuss "best practices" related to developmental assessment and reflected in the Head Start Program Performance Standards (Head Start Bureau, 1996); and illustrate the connection between developmental assessment and curriculum development. (author abstract)