Sequences with good autocorrelation Properties are useful for radar and communication applications. In this paper One Twenty Phase sequences are synthesized using Modified Genetic Algorithm (MGA). MGA is used as a statistical technique for obtaining approximate solutions to combinatorial optimization problems. This algorithm combines the good methodologies of the two algorithms like global minimum converging property of Genetic Algorithm (GA) and fast convergence rate of Hamming scan algorithm. The synthesized sequences have autocorrelation Properties better than well-known binary MPS code and Frank codes. The synthesized sequences also have complex signal structure which is difficult to detect and analyze by enemy electronics support measure.