Instructional implications of cognitive development theory are discussed, and it is proposed that the current theoretical framework offers a view of development that, applied in instructional contexts, leads to a reconceptualization of the traditional notion of developmental curricula. Piaget's theory offered a framework for how children should be taught and for what should be taught. It suggested to educators that learning across subject areas is interconnected and proceeds according to a developmental schedule. However, the promise that instructional sequences in the various disciplines could be integrated has never been fulfilled. New approaches that teach the components of the central conceptual structures and relations among them offer promise of coordinating instruction across subject areas. Current theory proposes to track conceptual understanding and interdisciplinary units. The current approach also allows teachers to make decisions regarding the timing of instruction on the basis of students' conceptual understanding. Students apply a given structure independently only when that structure is firmly in place. The present approach represents a move away from the Piagetian notion of a context-free, single, logical structure. A range of teaching approaches can be accommodated, and students' performance is judged in terms of their levels of understanding. One figure illustrates the central social structure, and there is a 14-item list of references. (SLD)