This work is intended to investigate a computational technique to predict the onset of transition. Most of the work, in this area is either experimental or empirical due to the notorious-reputation of solving-the governing Orr Sommerfeld equation. The adopted method here, called e" method, seems to be promising as an engineering tool over the other computational counterparts. The reason for that is due to its relative simplicity and its lower conditions of computer storage and time. In this study, the laminar boundary layer flow over a flat plate has been chosen as a case of study. Also, we investigate the effect of pressure gradient parameter on such a flow. The parameter (n) has proven not to be a universal constant. However, /t should be thoroughly investigated and calibrated to get its values with respect to the conditions of the problem being solved. The results also show very good agreements with the earlier experiments in some aspects and lesser agreements in others. The good agreements are in determining the critical Reynolds numbers and the determination of the onset location of transition, while less agreement appears in defining the unstable region