Following study investigates the weak form efficiency for Karachi stock market by taking monthly index data for the period of July 1, 1997 to July 2, 2011. Jarque Bera test, Kolmogorov Smirnov test, Unit root tests, Autoregressive Model, Run test and Variance ratio test employed to test the evidence of weak form efficiency. The results show that for selected sample period the Karachi stock market is not weak form efficient and hence not found to be random walk, therefore the rational investors can use the utility of the technical analysis in predicting the behavior of Karachi stock market at least in short run.