Squamous-cell carcinoma arising from a pilonidal sinus tract is an unusual complication of a common condition. Approximately 36 cases of carcinoma related to pilonidal disease have been reported in the literature. Wide excision with tumor-free margins has yielded five-year disease-free states in 55 percent of patients. Recurrence rates have been 44 percent to 50 percent in several large series. Regional (inguinal) nodal metastasis occurs in 14 percent of patients, heralding a dismal prognosis. Radiation and chemotherapy are of minimal palliative value. Reconstruction of these patients has consisted of split-thickness skin grafts or local cutaneous and myocutaneous flaps. Some authors have allowed healing by secondary intention. A case of squamous-cell carcinoma arising in a chronic pilonidal sinus tract is reported. Local recurrence required an extensive resection resulting in a large sacral/perineal defect. A single-stage reconstruction of this defect with multiple muscle and musculocutaneous flaps is described.