Questionnaires on individualized education programs (IEPs) were completed by 168 parents of handicapped children (10 to 17 years old). Analysis of the ten participant categories (i.e., mother, teacher, psychologist) found that two participant categories, the child's mother and the special education teacher, attended at least one IEP conference 75% of the time. IEP participant attendance significantly varied by each handicapping condition, age level, and type of school district. Four factors were suggested as causes of lack of participation in IEP conferences: (1) poor coordination and communication between interdisciplinary team members; (2) negative attitudes of specific interdisciplinary teams' responsibilities; (3) unavailability of professional staff for conference participation; and (4) a lack of knowledge about P.L. 94-142 (the Education for All Handicapped Children Act). (CL)