A tourniquet is often used in total knee arthroplasty resulting in improved visualization of structures, reduced intraoperative bleeding and better cementation. The risks include deep vein thrombosis and pulmonary embolism. To quantify the case for or against tourniquet use, we carried out a systematic review and meta-analysis of selected randomized controlled trials. Ten studies were included in the meta-analysis. Of the 8 outcomes analyzed (surgery duration; total, intraoperative, and postoperative blood losses; deep vein thrombosis; pulmonary embolism; and minor/major complications), the total and intraoperative blood losses were less using a tourniquet. Minor complications were more common in the tourniquet group. The remaining outcomes showed no difference between the groups. Using a tourniquet may be beneficial, but long-term studies of outcome are needed.