Objectives. Immunological, biochemical and physicochemical analysis of oral fluid in children with congenital cleft palate. Purpose. To analyze oral fluid in children with congenital cleft palate to determine the levels of cytokines (IL-2, IL-4, IL-6), lysozyme, secretory immunoglobulin A, interferon gamma and evaluate biochemical (calcium, magnesium, phosphorus, protein) and physicochemical (salivation rate, kinematic viscosity, pH) parameters of mixed saliva. Methodology. The article presents the results of a laboratory study of the parameters of the oral fluid of 90 children aged 2–5 years with congenital cleft and 45 practically healthy children of the same age. Results. In children 2–5 years old with congenital cleft palate, according to immunological parameters of the oral fluid, there is a decrease in the amount of cytokines in the oral fluid (IL-2, IL-4, IL-6), lysozyme, secretory immunoglobulin-A, interferon gamma, which indicates deficiencies of local immunity in the oral cavity and low resistance to bacterial infections. An increase in the kinematic viscosity of the oral fluid and a decrease in protein levels were noted. Conclusions. Laboratory confirmation was obtained of the presence of a local inflammatory process in the oral cavity and a decrease in local immunological anti-inflammatory factors in the oral fluid. Changes in the immunological and rheological properties of oral fluid in children with congenital cleft palate lead to disturbances in the process of self-cleaning of the mucous membrane and teeth, which in the postoperative period creates high risks for the formation of infection and inflammation of the wound after uranoplasty.