The advantages and disadvantages of endoscopic compared with open carpal tunnelreleasearecontroversial. We have performed a prospective, randomised, blinded assessment in a district general hospital in order to determine if there was any demonstrable advantage in undertaking either technique. Twenty-five patients with confirmed bilateral idiopathic carpal tunnel syndrome were randomised to undergo endoscopic release by the single portal Agee technique to one hand and open release to the other. Independent preoperative and postoperative assessment was undertaken by a hand therapist who was blinded to the type of treatment. Follow-up was for 12 months. The operating time was two minutes shorter for the open technique (p < 0.005). At all stages of postoperative assessment, the endoscopic technique had no significant advantages in terms of return of muscle strength and assessment of hand function, grip strength, manual dexterity or sensation. In comparison with open release, single-portal endoscopic carpal tunnel release has a similar incidence of complications and a similar return of hand function, but is a slightly slower technique to undertake