The study reports on a comparative analysis of behavior disorder definitions and eligibility criteria for special education cooperatives (N=90) in the state of Illinois. Data regarding entrance and exit criteria and referral, evaluation and program placement procedures are evaluated. Among results were that 35% of respondents reported that no guidelines for the identification of behavior disorders in children were in use; that 24% used the Illinois definition; that though 84% reported entrance criteria for programs, only 29% used established program exit criteria. Typical entrance criteria included duration of the behavior and documentation of unsuccessful intervention attempts. Program implications are reviewed and the need for definitional and diagnostic consensus is discussed. (Author/DB)