The purpose of this study was to determine the effects of tourniquet use for routine knee arthroscopy based on both subjective and objective functional outcome measures. The study was a prospective, double-blind, randomized clinical trial. There were 120 patients randomized to tourniquet inflation (300 mm Hg) or no tourniquet inflation during routine knee arthroscopy. Patients recorded their average pain on a visual analog scale and their narcotic use for the previous 24 hours, for the first 5 postoperative days. Patients also completed a preoperative and postoperative (2 week, 6 week, 3 month) Western Ontario and McMaster University Osteoarthritis Index (WOMAC), 6-minute walk, 30-second stair climb, 1-leg standing vertical leap, range of motion, and isokinetic strength testing. Time to return to work and sport was documented. No statistically significant difference was found between tourniquet-up and tourniquet-down groups for the WOMAC quality of life measure, functional tests, isokinetic muscle strengthening, or time to return to work or sport (t test/repeated measures analysis of variance). However, there was a trend for less early postoperative pain and slightly better isokinetic strength testing at 2 weeks in the tourniquet-down group. Visualization was rated by surgeons to be 3 times better in the tourniquet-up group, although mean operative time did not differ between the groups. The use of a pneumatic tourniquet at 300 mm Hg does not significantly effect overall patient quality of life or functional outcome following routine knee arthroscopy.