This paper deals with the role of the child developmentalist in improving interdisciplinary assessment and treatment of children with behavioral and learning problems. A specific task of Developmental Services of the Texas Research Institute of Mental Sciences was to optimize the utilization of professional staff in a development assessment clinic. Clinic procedures utilized force-field analysis principles adapted to a problem-oriented record and an interdisciplinary staff consisting of medical, social work, clinical psychology and child development specialists. Focus for the child developmentalist was primarily on screening of children from birth to six years. The unique perspective of each discipline was represented and incorporated into the management plan. Illustrations are given of how the child developmentalist emphasizes the significance of developmental sequences and adds an understanding of the importance of the context in which behavior occurs as well as the context in which the child develops. The child developmentalist identifies critical points in parent-child and child-environment interaction patterns and indicates to the parents how they may be able to change the developmental outcome of their children. (Author/BF)