The present invention relates generally to an emergency tourniquet for rapidly and easily reducing or stopping blood flow to an injured limb. The tourniquet utilizes a closed loop system that is formed by passing a portion of a twistable strap, which comprises the loop, through a side opening in a buckle and cinching the strap tightly above an injury and thereafter twisting the strap. Otherwise, a loop may be formed and the injured limb passed through the loop prior to tightening it about the injured limb. The buckle includes an elongated opening that accepts an end or edge of the twistable strap. A free end of the twistable strap passes into a J-hook opening and is secured therein. The strap is then twisted and a notch in the buckle is hooked on an edge of the twistable strap. Bulbous regions are provided on either end of the buckle. A base plate may also be included for further securing the buckle in place to maintain the tourniquet in place until it can be removed by a competent medical professional.