Objective: To test the null hypothesis of no significant difference between intraoral pressure characteristics in infants with cleft lip and palate (CLP) with or without presurgical orthopedic (PSO) plates (groups CLP and CLP-PSO), compared with noncleft infants. Materials and Methods: Intraoral atmospheric pressure assessments were performed on 17 subjects with preoperative CLP (m/f, 11/6; mean/SD, 4.76/0.92 months) and a matched control group (n 5 24; m/f, 15/9; mean/SD, 4.88/0.9 months), for 200 seconds, simultaneously at the vestibulum (vestibular space [VS]) and at the palate (subpalatal space [SPS]), using a prepared pacifier connected to a digital manometer. Areas under the pressure curves (AUC), frequencies, durations, and magnitudes of swallowing peaks and pressure resting plateaus were compared between trial groups and locations (VS, SPS) using a two-factor analysis of variance for repeated measures, Kruskal-Wallis test, and Mann-Whitney U-test (a 5 .05). Results: The null hypothesis was rejected: Globally, there were statistically significant differences in intraoral pressure characteristics between groups CLP, CLP-PSO, and control (all P , .01), with significantly higher negative pressures (AUC) in the control subjects compared with those of CLP or CLP-PSO. There were significant effects by the location of pressure recordings (VS, SPS) and their interaction with all treatment groups. Differences between noncleft and CLP subjects were more pronounced in the VS than in the SPS. There was no significant effect by PSO. Conclusion: PSO does not improve deviated swallowing characteristics during suction in CLP infants. (Angle Orthod. 2016;86:315-323.)