The objective of the research study was to determine the effect of wholemeal oat flour storage on changes in a content of total (TDF), soluble (SDF), and insoluble (IDF) dietary fibre and in rheological properties of wholemeal oat flour. The analysis included the flours milled from naked oat grain in a laboratory. Those oat flours were stored for 3 months at temperatures of 20 ºC, 4 ºC and -20 ºC. The apparent viscosity (initial, maximal, final, setback) was determined in 5 % (w/w) water-based suspensions. Regardless of the storage temperature, an increase was reported in the content of IDF as was a decrease in the content of SDF during the 3-month period of storing flour. The widest range of changes in the individual dietary fibre fractions was reported during storage at 20 ºC. The changes in the rheological properties depended on the time and temperature of oat flour storage. The largest changes were reported in the case of the setback value during storage at 20 ºC and 4 ºC. The smallest range of changes in all the rheological properties was found in the flours stored at -20 ºC. During the 3-month period of storing flour the range of changes in the rheological properties was inconsiderable and it did not depend on the contents of individual dietary fibre fractions, therefore it should not have any significant effect on the changes in the technological properties of flours. No unequivocal dependences were reported between the changes in the content of dietary fibre fractions and the rheological properties. During the entire 3-month storage period, the smallest changes occurred in the dietary fibre composition and rheological properties of oat flour during storage at the -20 ºC temperature.