One-hundred patients undergoing radial forearm flap reconstruction in the head and neck over a 2-year period were followed prospectively to assess complications and morbidity associated with the radial flap donor site. Eighty-six patients were available follow-up at 3 months and 74 at 1 year (49 fasciocutaneous, 25 composite). Partial loss of the donor-site skin graft occurred in 14 patients (16 percent), with exposure of tendons in 11 patients (13 percent). Delay in healing of the split-thickness skin graft at the donor site occurred in 19 patients (22 percent). Fracture of the radius occurred in 6 of 35 patients with composite flaps (17 percent). Superficial radial nerve sensation was reduced in 24 patients (32 percent) at 1 year. Ten patients (14 percent) reported cold intolerance, and 21 patients (28 percent) complained of poor aesthetic result. Function of the donor arm was restricted in 8 patients (16 percent) in the fasciocutaneous group, in 7 patients (36 percent) in the composite group without fracture, and in all patients who had a fracture of the radius following harvesting of composite flaps. Detailed measurements of forearm circumference, grip strength, pinch strength, and wrist movements showed greater reduction in these parameters in patients reporting restricted function compared with those reporting normal function. It is concluded that there is a low incidence of long-term morbidity associated with fasciocutaneous flaps and a higher incidence with composite flaps. Fracture of the radius results in reduced function in all cases.