AIM: Introduction of a safe and reliable method for reconstruction of soft tissue defects after excision of T1-T2 and borderline carcinomas of the posterior part of the oral cavity and mesopharynx. METHOD: Operation of two male patients suffering from tonsillolingual carcinoma, one with recurrent tumour after irradiation, the other with untreated primary and neck metastasis. After excision of the tumour with mandibular splitting method only a random buccal transposition flap was applied for reconstruction. The flap was adapted anatomically into the defect. It is a modification of previously described methods. RESULTS: Both patients healed primarily with undisturbed blood circulation of the flap. The functional rehabilitation period was short, the flap tolerated the postoperative irradiation, a moderate trismus remained after completion of the treatment, but it was not attributable to the flap. CONCLUSION: The use of the single buccal transposition flap for reconstruction of smaller defects of the posterior part of the oral cavity seems to be a simple, reliable and safe method even after irradiation. The key of the acceptable functional results is the correct adaptation of the flap