Regression testing is testing the software in order to make sure that the modification made on the program lines does not affect the other parts of th e software, it is in maintenance phase and accounts for 80% of the maintenance cost and thus optimizing reg ression testing is one of the prime motives of software testers. Here we take the advantage of sel ecting test case information available in regressio n testing and prioritize them based on the number of modified lines covered by the test case, the test c ase which covers the most number of modified lines has the highest priority and is executed first and the one with the least coverage of modified lines has the l owest priority and is executed last provided deadli ne time is not reached, thus even if the testing is no t finished we will have covered maximum modified lines, the prioritization of the test cases are don e using the genetic algorithm, the genetic algorith m takes test case information from regression testing as in put and produces a sequence of test case to be exec uted such that the maximum number of modified code is covered.