The donor site defect remains the major disadvantage of the radial forearm free flap (RFFF). The purpose of this case series was to evaluate the effectiveness and safety of a local bilobed flap in direct closure of the RFFF donor site defect.Between February 2017 and July 2017, a prospective study was designed with 13 patients who had undergone RFFF reconstruction of the oral cavity. The primary purpose was to assess the effectiveness and safety of a bilobed flap closure of the RFFF donor site with primary healing. The late endpoint was to evaluate functional morbidity of the donor hand by comparing preoperative and postoperative outcomes.The donor site defect healed primarily in 12 of the 13 patients. A small area of skin necrosis (4%) developed in one patient, which was managed conservatively and healed by secondary intention. A significant reduction of wrist extension (mean difference [MD] = 2.64°, P = .01) and grip strength (MD = 3.68 kg, P = .04) was observed between preoperative and postoperative measurements. No statistically significant difference was observed regarding flexion, radial deviation, ulnar deviation, supination, pronation and pinch strength (P > .05).The bilobed flap is a reliable and effective method for closure of a RFFF donor site defect, ≤5 cm in greatest length. The advantages are excellent regional skin color match and avoidance of a second donor site and its inherent complications.