Spectroscopy scan is highly sensitive to frequency drift during the acquisition. Although most spectroscopy sequences do not create large frequency drift themselves, it is problematic when they are run immediately after sequences with high gradient duty-cycle, as the frequency still drifts due to gradient cooling. In this paper, realtime frequency adjustment was implemented for MEGA-PRESS sequence for GABA J-editing. FID signal was read during water suppression and used to calculate and update the system frequency every TR cycle. It was tested on a phantom and in vivo and showed effectiveness by providing insensitivity to the frequency drifts during the acquisition.