A convenient calibration method for pH measurements in monoethylene glycol (MEG) + water solvents is described. The calibration has to be performed once for each electrode type. pH measurements were performed in CO2(g, similar to 1 bar)-saturated solutions of 60 and 90 wt % MEG at 4-80 degrees C with varying NaHCO3 and KHCO3 contents. Reproducible data were obtained using several different electrodes. Theoretical aspects are reviewed.