Surgical reconstruction of large head and neck tumors involves great problems. Preoperative irradiation increases the risk of postoperative complications. The use of microvascular free flaps has definitive advantages over conventional reconstruction techniques and permits immediate preoperative high-dose radiation therapy. Eighty-eight patients, 55 (62%) men and 33 (38%) women, with head and neck tumors underwent microvascular reconstruction at the Turku University Central Hospital in 1985-1995; 77 of them were irradiated before surgery. All irradiated patients underwent primary reconstruction. The preoperative radiation dose was 50-65 Gy. The free tissue transfer was successful in 77 (88%) of the 88 patients. The success rate was 87% in irradiated patients and 91% in nonirradiated patients. Free tissue transfers are suitable for one-stage reconstruction in selected patients such as those receiving high-dose preoperative irradiation. The transfer of microvascular free flaps to the head and neck has become the most common reconstruction method owing to its increasing success rates as well as its excellent esthetic and functional results.