With the enactment of the "Education for All Handicapped Children Act" of 1975, all children are entitled to appropriate free education and related services regardless of disabilities. As a result, major strides have been made toward providing services for developmentally delayed children. To gain access to these services, children who are suspected of having developmental or physical disabilities have to be referred to trained and qualified individuals or multi-disciplinary teams for assessment. Young children, however, are difficult to assess accurately. Current trends in preschool assessment include a move away from a "single assessor" model to an environmental model which is designed for the individual child. The following characteristics of preschool assessment are described: (1) criterion referenced and process oriented; (2) informal, indirect, and naturalistic evaluations; and (3) handicap accommodating assessments. Because single discipline evaluations provide a "snap shot" from a limited perspective, assessments involving more than one discipline are recommended. The role of mental health practitioners is discussed. (JBJ)