In order to define the role of two-portal endoscopic carpal tunnel release, a prospective randomised study with an independent observer was performed to compare endoscopic and open surgery. Thirty-two hands in 29 patients, with symptoms, clinical signs and EMG changes consistent with idiopathic carpal tunnel syndrome were randomised to either endoscopic carpal tunnel release or open release. No significant difference in sick leave between the two groups could be found, being a mean of 17 days (range 0-31 days) with endoscopic surgery, and 19 days (range 0-42 days) with open conventional surgery. No differences in surgical results were found, but three patients in the endoscopic group suffered transient numbness on the radial side of the ring finger.