OBJECT: The authors have developed a novel technique for percutaneous fusion in which standard microendoscopic discectomy is modified. Based on data obtained in their cadaveric studies they considered that this minimally invasive interbody fusion could be safely implemented clinically. The authors describe their initial experience with a microendoscopic transforaminal lumbar interbody fusion (METLIF) technique, with regard to safety in the placement of percutaneous instrumentation, perioperative morbidity, and early postoperative results. METHODS: The METLIF procedure was performed unilaterally in 20 patients with single-level lumbar spondylolisthesis or pure mechanical back pain with endoscopic assistance, hemilaminectomy, unilateral facetectomy, and microdiscectomy. Two interbody grafts were placed via the lateral exposure of the disc space. Bilateral percutaneous pedicle screws were then inserted. Compared with patients who had undergone single-level posterior LIF at the same institutions, intraoperative blood loss, hospital length of stay (LOS), and postoperative narcotic agent use were significantly lower in the METLIF group. The mean LOS for the percutaneous fusion group was 3.4 days (5.1 days in those who underwent PLIF; p < 0.02). There have been no procedure-related complications in this series to date. CONCLUSIONS: The METLIF technique provided an option for percutaneous interbody fusion similar to that in open surgery while minimizing destruction to adjacent tissues. This technique was safe and exhibited a trend toward decreased intraoperative blood loss, postoperative pain, total narcotic use, and the risk of transfusion.