This document analyzes states' definition of developmental delay and analyzes current eligibility classifications and criteria used by states to identify young children in need of special education and related services. Data were obtained from states' Web sites, the National State Policy Database (2003), and/or provided by coordinators of the state Part B-Section 619 programs, including the District of Columbia. The paper describes variations among state policies in disability terminology used for young children, age ranges used by states for developmental delay, the relationship between developmental delay and other Part B categories, and eligibility criteria for developmental delay. The author concludes that states exhibit a strong interest in using the option of a developmental delay eligibility category for young children served under the Individuals with Disabilities Education Act (IDEA). Four tables provide information on the following: (1) Part B Disability Categories under IDEA; (2) IDEA Regulations Related to Developmental Delay for Children Ages 3 through 9 Years; (3) Summary of State Eligibility Classifications and Criteria for Young Children under Part B of IDEA; and (4) Summary Table of Early Childhood Special Education Eligibility Criteria in the States, and the District of Columbia as of January 2004. (Contains 4 tables.)