Test case prioritization involves scheduling test cases in an order that increases the effectiveness in achieving some performance goals. One of the most important performance goals is the rate of fault detection. Test cases should run in an order that increases the possibility of fault detection and also that detects the most severe faults at the earliest in its testing life cycle. In this paper, the authors develop and validate requirement based system level test case prioritization scheme to reveal more severe faults at an earlier stage and to improve customer-perceived software quality using Genetic Algorithm (GA). For this, they propose a set of prioritization factors to design the proposed system. In their proposed technique, they refer to these factors as Prioritization Factors (PF).