The objective of the research study was to produce and assess the quality of koumiss made from donkey’s milk. Prior to the production, the basic composition of raw material was determined, i.e. the content of protein, fat, and lactose; also, the pH value and titratable acidity of milk were measured, and the total count of microbes was determined as were the counts of psychrotrophs and yeasts in raw milk. As for the koumiss, its pH value was measured, the acidity as well as the content of lactose and alcohol therein were determined. Also, the counts of Lb. delbrueckii ssp. bulgaricus, Lb. acidophilus, and of yeast during the ripening of koumiss were assayed. An electrophoretic separation was performed of proteins in the raw material and in the koumiss to assess the proteolysis of milk proteins during the fermentation and ripening. The donkey’s milk was characterized by the following percent levels: the content of proteins: 1.29 %; the content of fat: 0.17 %; and the content of lactose: 7.20 %. The total count of microbes in raw milk was 5.6×10² CFU/ml. The results of the analysis confirmed the high quality of the koumiss analyzed. During the fermentation and ripening, 30% of lactose was fermented by the microflora used in the process. On the 14th day of ripening, the count of Lb. delbrueckii ssp. bulgaricus was 2.29×10⁷ CFU/ml, the count of Lb. acidophilus: 4.37×10⁷ CFU/ml, and that of yeast: 1.12×10⁷ CFU/ml. The content of ethanol in the product did not reach the content level as recommended by the Codex Alimentarius (not less than 0.5 %). The koumiss analyzed was characterized by a high microbiological quality. Based on the results of electrophoresis it was possible to estimate the content of lysozyme in the donkey’s milk and the changes in the fractions of casein during ripening. A decrease was found in the content of casein proteins in the total proteins contained in the koumiss. A low content of ethanol in the studied koumiss from donkey’s milk could be contributed to the fact that only one species of yeasts was present therein. Based on the results of the research, it was concluded that donkey’s milk can be a good raw material to produce fermented beverages with functional features.