The objective of this study was to determine the influence of a production method of red beet leaven on its quality and usefulness for the preparation of traditional red beet soup. Two methods of red beet leaven fermentation were used: a traditional method with rye bread added, and a method using Lactobacillus plantarum as a starter. With these two methods of fermentation used, the authors produced red beet leavens of the equally good quality. At the same time, it was stated that the preparation method of leavens influenced the level of lactic acid bacteria in the final leaven product, whereas the total mesophilic bacteria and yeast counts were comparable in the leaven with bread and with inoculum. The leavens produced had a red-violet color hue, a taste and an aroma appearing typical for red beet. From the sensory point of view, the leavens prepared were found desirable and useful for the preparation of a Polish traditional red beet soup (the so called borscht).