Skin flaps were raised on ten dogs and a dermal graft was placed under the experimental flap. At selected postoperative intervals the circulation of the flaps was evaluated by determining the clearance half-times of an intradermally injected radioisotope. Comparison of clearance half-time values of the experimental and control flaps indicate that circulation and, therefore, revascularization are not significantly altered by the insertion of a dermal graft under a skin flap. The apparently increased incidence of wound breakdown in patients who have had dermal grafts employed in head and neck surgery is therefore felt to be related to factors other than interference with revascularization of overlying skin flaps.