Palatal soft-tissue expansion might be appropriate for use in cleft palate surgery. Seventy-five cats were divided into four different experimental groups and one control group. Intraoral tissue expansion was started at the age of 14 weeks in normal or scarred mucoperiosteum. The experiment lasted until 24 weeks of age. Serial standardized lateral cephalograms from each animal were digitized, and the results were statistically analyzed. The results indicate that the effects are independent of the presence of scarred tissue, that sagittal growth is impaired by tissue expansion, and that the tissue expander induced resorption of palatal bone.