This paper presents the methodological aspects of the measurement of oxygen flux in the soil by voltammetric method with the use of three- (with potentiostat) and two-electrode systems. The studies were performed on artificially prepared samples of Polish mineral soils. It was found that the averaged limits of the integration range (quasiplateau) in voltammetric measurements of the potential oxygen flux in the soil, obtained for measured soil samples of Polish mineral soils investigated, were: -460÷ -700 mV for the three-electrode system and -1260÷ -1600 mV for the two-electrode system. The OFD values obtained with the use of voltammetric method follow the lognormal distribution. Uncertainty of the results obtained with the use of the three-electrode system is smaller than for the two-electrode system. However, this does not make it impossible to use the two-electrode system, especially for measurements in compacted soils, where installation of the electrode in glass body is a technical problem and in the aspect of simultaneous measurements of OFD and soil water content by TDR technology with the same probe.