This document uses a question-and-answer format in clarifying the meaning and use of the term "informed clinical opinion," which appears in the regulatory requirements for the implementation of Part H of the Education of the Handicapped Act Amendments 1986 (Public Law 99-457) as an integral part of an eligibility determination. The paper points out that "informed clinical opinion" must be included in evaluation and assessment procedures as a necessary safeguard against eligibility determination based upon isolated information or test scores alone. Individuals and agencies need to consider who might have an informed clinical opinion, what these people might have an informed clinical opinion about, and how their informed clinical opinion can be integrated into the process of evaluation and assessment. Informed clinical opinion should be taken into account at both the level of the individual early intervention professional and the level of the multidisciplinary team. The regulations are intended to ensure a dynamic assessment approach, support the acquisition and interpretation of multiple sources of information as part of the evaluation process, and permit greater compatibility between a child and family's needs and the provision of services. The paper reprints relevant Part H regulations. (JDD)