A major disadvantage of free radial forearm flaps is the conspicuous donor site. However, there have been few studies on donor scars. The authors evaluated the donor site in patients who underwent oral-floor reconstruction with a free radial forearm flap. The subjects were 23 patients (19 males and four females) who underwent reconstruction with a free radial forearm flap following resection of a malignant oral tumor, and were followed for 1 year or longer. The fasciocutaneous flap collection site was closed by full-thickness skin graft (FTSG) from the groin with tie-over dressing. All grafts took perfectly. At the scar at the donor site, five items (pigmentation, scar width, depression, wrist mobility, and sensory abnormalities) were evaluated. Depression and pigmentation were often observed, but patient dissatisfaction was slight. While their main postoperative concern was the oral reconstruction site, after about 1 year, the donor site became more important to patients. However, the results were good. A 100 percent take of the FTSG at the donor site should produce good results. Surgeons should pay adequate attention not only to the outcome at the reconstruction site, but also to the closure of the donor site.