Microendoscopic discectomy (MED) is one of the minimally invasive endoscopic procedures for treating lumbar disc herniation. We have applied MED techniques to posterior decompression procedures for treating lumbar spinal stenosis (LSS). In the present study, we examined the surgical complications in 114 consecutive patients surgically treated with MED procedures for LSS. Intraoperative complications occurred in 9 patients. Six patients (5.3%) experienced a dural tear, and three (2.6%) had a fracture of an inferior facet. Early postoperative complications occurred in 13 patients. Twelve patients (10.5%) experienced transient neurological complications. The clinical outcomes at the mean 28-month follow-up were not affected by these surgical complications. Other major complications such as nerve injury and surgical site infection were not observed. Most of the complications occurred in the initial series of patients, and the incidence of complications decreased with an increase in the surgeon's experience and the application of several preventive measures against the complications. The surgeon should undergo training when MED techniques are applied in surgical treatment in order to recognize the specific complications associated with such procedures and apply preventive measures against these complications.