The resistivity ratio due to gas bubbles underneath horizontal anodes in electrolytic cells was measured and compared with that in an air-water model of identical geometry. It was found that at equal current density or equivalent gas generation rate, the difference in the bubble resistivity ratio between these two situations can be up to 20%. Consequently, the results obtained from an air-water model cannot be directly applied to an electrolytic cell. Results also showed that within the range of experimental conditions covered, the bubble resistivity ratios obtained for a given anode-cathode distance in both cells are linearly related to the bubble coverage ratio, based on bubbles greater than a certain size as limited by the measurement method.