Introduction. The objective of the present article is to determine the molecular weights of the protein mixture of the cow colostrum. This will lead to the development and production of immuno-prophylactic products for maintaining immunity human body.Materials and methods. Bovine milk was the main material for the study. The test samples have been selected from the first day of calving and during the following three days. Specimen 1 represented the colostrum of the cows from Zhytomyr region (Berdychiv town). Specimen 2 represented the bovine colostrum from Kyiv region (Tetiiv town). Electrophoresis method in the polyacrylamide gel in the Laemmli system.Results. It has been determined that high molecular weight fractions of colostrum contain protein molecules with molecular weights of 160-190 kDa, among which are immunoglobulins. Separate parts of immunoglobulins and other proteins, namely, IgG (55kDa) and IgA (62kDa) heavy chains, secretory component of sIgA, and lactoferrin, have also been found out.The test samples of high molecular weight peptides of colostrum contain the biologically active fragments among which there are mostly immunoglobulins, their parts, proteinsabzymes, other protein fragments. The proteins with the molecular weight of 80, 62, 55 kDa are also determined, they can represent heavy chains (55 kDa) and light chains (25 kDa) of IgG and sIgA. In particular, sIgA is a supermolecular complex consisting of Н-and L-chains of IgA (62, 25 kDa, respectively) and a secretory component (80 kDa). Apart from the secretory component of IgA, the protein molecules with the molecular weight of 80 kDa can be halves of the molecules of immunoglobulins or lactoferrin.Conclusion. The presence of a large quantity of proteins allow using the colostrum in the production of childhood, functional, medical, and prophylactic nutrition; in biotechnologies for the manufacturing of other food products with a special composition; in medicine and pharmacology to produce food-grade coats and capsules for medical substances, dietary food supplements.