In software product development, it is impossible to test an entire product. To do so would increase the cost of quality and the time of the product release cycle, without providing adequate return on investment. Therefore, it is important to identify the critical areas of the software and test those more rigorously than other areas. Identifying critical areas is also important because the testing phase is often at the far end of the product release cycle and is often shortened by missed deadlines in other areas of the product release cycle. This results in many sleepless nights for test engineers who work hard to meet delivery deadlines. Therefore, testing needs to be prioritized based on a well-defined strategy and approach to enable the best possible use of time and resources. This paper describes a methodology for identifying significant test cases for a given release.