Oxygen concentration measurements in clay soils that are representative of a soil layer are difficult to obtain. Distribution of oxygen is strongly related to the soil structure, and, therefore, reliable oxygen concentration measurements in clay soils require a description of the soil structure. A procedure for obtaining combined measurements of soil structure and oxygen concentrations is presented in this paper. Oxygen micro-electrodes are used to measure the oxygen concentrations directly in the soil, while the soil structure is concurrently determined with the aid of computer assisted tomography scanning. Good agreement was found between the soil structure and oxygen concentration distributions.