The performance of two developmentally delayed Down's Syndrome children on the Uzgiris-Hunt Scales (UHS) of psychological development is discussed in detail to illustrate the applicability of the scales to developmentally delayed children. This work was carried out at the Garden Park School for trainable and multiple-handicapped children in Phoenix, Arizona. The children at the school, ranging in chronological age from 2 to 5 years, are seen two mornings a week for two hours. The UHS is theoretically based on Jean Piaget's proposition that simple, easily observed behavioral interactions in the human infant and young child reveal development, consolidation, and elaboration of cognitive structures. The UHS consists of a specified number of tasks in each of six scales. Each scale reveals an invariant sequence of developmental attainments. Researchers have demonstrated a relationship between performance on the Scales and adaptive behavior in young, developmentally disabled children. Administration of the scales with developmentally delayed children is best aided by the use of videotape replay and is best conducted by a teacher familiar with the children. The performance of the two Down's Syndrome children, recommendations for classroom follow-up of these children, and interpretations of Scales I, II, and III are discussed. (Author/SS)