Maxillary plaster models of untreated infants with various cleft lip and palate forms have been studied under the Reflex Microscope. From the three- dimensional data processed by a PC, the specific dimensions of various cleft forms can be determined. Unexpected findings are that skeletal maxillary changes are present in infant velar clefts. The mid-sagittal maxillary length in particular becomes shorter with more severe clefting of the bony palate. From the morphologic point of view, Robin's sequence does not represent a specific entity, but usually a severe cleft of the hard palate. Unilateral clefts of lip, alveolus, and palate with a partial cleft lip reveal worse malformations than complete unilateral clefts. The morphologic changes recorded can be explained by a varying degree of lingual malposition. This reveals that displacements and malformations of infant cleft lip and palate are in fact secondary in nature. In correcting these secondary surface manifestations as soon as indicated by physiologic criteria one could hope for early normalization of sensation, perception, and function. Three-dimensional high-precision measurements are crucial for data-objective diagnoses, timing of therapy, choice of treatment, and in later evaluation of the results.