This study reports on 565 consecutive endoscopic carpal tunnel releases using the Agee one-portal technique of which 25 (4.4%) were converted to the open technique. The follow-up period was from 4 to 52 months. Immediate symptomatic relief was reported in 562 wrists (99.5%). There were 25 complications (4.4%) including pillar pain (8 wrists), digital neuropraxia (n = 6), median nerve contusion (n = 3), incomplete division of the flexor retinaculum (n = 3), superficial infection (n = 3), reflex sympathetic dystrophy (n = 1), and tenderness of the scar (n = 1). We describe the evolution of our selection of patients and surgical technique. We recommend caution in performing ECTR in short patients who are liable to have small wrists because of the risk of contusion of the median nerve. We present some technical modifications that may make the technique safer.