The buccal fat flap is an encapsulated mass originating from a specific fat tissue that is easily accessed and richly vascularized. The aim of this study was to report the effect of using the buccal fat flap on the oronasal fistula rate in primary palatoplasty. A case-controlled study of 94 patients who underwent primary cleft palate repair. Patients were divided into two groups: (1) two-flap palatoplasty with buccal fat flap for coverage of lateral hard palate defect and (2) conventional two-flap palatoplasty. The incidence of oronasal fistula and postoperative complications were compared between groups. Multivariate analysis was performed to determine the risk factors of oronasal fistula development. Forty-seven patients in each group demonstrated the same baseline characteristics. The buccal fat group showed a significant lower postoperative oronasal fistula rate (2.13 percent versus 21.28 percent, p = 0.008) and smaller fistula size (2 mm versus 4 mm, p = 0.049). A cleft width wider than 11.5 mm increased the odds ratio of fistula formation by 8.44-fold (p = 0.047), and the use of buccal fat protected against postoperative palatal fistula formation (OR, 0.08, p = 0.019). The use of buccal fat flaps for lateral hard palatal defect coverage in primary palatoplasty can reduce the rate of postoperative palatal fistula, especially in cases of wide palatal cleft. Therapeutic, III.