Carpal tunnel syndrome (CTS) is the most common compressive neuropathy of the upper extremity. Compression of the median nerve at the wrist can cause hand pain, numbness, tingling and motor weakness. CTS initially is addressed with non-operative measures. When non-operative treatment fails then surgical release of the transverse carpal ligament (TCL) is indicated. Numerous surgical techniques have been described to release the TCL and decompress the underlying median nerve. The open CTR (OCTR) approach remains the gold standard and the most commonly used technique. Approximately 500,000 CTRs are performed every year in the US. A sick leave of at least 30 days per year is documented in about 45% of people with CTS, with a median of 28 days absent from work. Endoscopic carpal tunnel release (ECTR) techniques were introduced to reduce morbidity and expedite recovery from surgery. ECTR offers the theoretical advantages of reduced postoperative pain, faster recovery of grip strength, earlier return to work and activities of daily living, and fewer wound-related complications. Amongst the endoscopic techniques that have been developed the last decades, our preferred one is the single proximal portal approach described by Agee in 1992. This chapter describes in detail the single proximal portal ECTR technique.