Dysfunctions of the reproductive system in bitches are a severe problem. Studies were conducted to understand the main differences in the receptor activity of immunocompetent cells in the different conditions of the reproductive system to determine the functional activity of lymphocyte and progesterone surface receptors. Three groups of breeding bitches (a total of 15 animals) were developed to analyze the immunohistochemistry characteristics of the uterus. The immunohistochemical method was used to type cells using monoclonal antibodies. Uterine tissue samples from all groups showed variable amounts of cytotoxic lymphocytes (those with CD8 receptors). Nonetheless, isolated cells were discovered strewn across the stroma in groups 2 and 3. In the anaesthetic group, cytotoxic lymphocytes were scattered in the functional layer of the mucosa in the part closer to the uterine lumen, and lymphocytes were located singly in the stroma around the excretory parts of the glands and among the epitheliocytes. The study of the activity and topography of progesterone receptors in the uterine structures of the studied animals showed that the glandular epithelium of all the groups had extremely low progesterone cell reactivity. All of the examined samples showed a clear positive response (progesterone receptors) in the endothelium of the endometrial capillaries. The established peculiarity of progesterone receptor distribution in different structures of the uterus depending on the functional state of the reproductive system confirms the significant role of progesterone in the genesis of dysfunctions and is likely to be a sensitizing factor.