An arthroscopic technique utilizing a single tunnel has been developed for placing an anterior cruciate ligament (ACL) graft (a loop of semitendinosis tendon) along the anatomic axis of the normal ACL. Postoperative radiographs and direct arthroscopic visualization with intraoperative isometry testing of the graft have confirmed the anatomic position of the single tibiofemoral tunnel. Arthroscopic ACL reconstruction using the single tunnel technique has been performed on 38 patients and 40 knees. The longest follow-up period is 42 months. Postoperatively the pivot-shift test has been universally negative and no patient, subjectively or objectively, has reported giving way of the knee. Few complications have been reported using this technique. The procedure can be performed on an outpatient basis.With the use of a single tunnel, graft insertion is facilitated and, as there are less bends in the graft, it appears to be better biomechanically than traditional two-tunnel techniques. The early results of this technique are most encouraging; the technique could become a standard procedure for the experienced arthroscopist and knee surgeon.