This article describes the development of a computer-based assessment system for children in early childhood programs, The Indiana Assessment System of Educational Proficiencies: Early Childhood (IASEP: EC). Skills in five developmental domains (i.e., cognitive, communication, social, sensory motor, and self-help) were selected and content validated using a representative stakeholder and expert panel process. Resulting indicators were included in assessment software and piloted with 40 teachers and 128 children between the ages of 3 and 6 years. Analysis of core ratings yielded four separate factors: language development, social development, sensory motor development, and self-help skills. The rotated factor structure was largely consistent with the initial domain structure. Correlations between IASEP: EC domain ratings and the Speed DIAL and Picture Naming Task suggest a strong positive relationship between the developmental constructs measured by each. Initial results would lend support for the reliability and validity of the IASEP: EC rating system. Implications for using teacher ratings with portfolio evidence as a means of providing comprehensive documentation of child growth are discussed. (Contains 7 tables.)