Introduction: The aim of the study was to evaluate the correlation between the presence of anti-C. trachomatis (C.t.) antibodies in serum and expressed prostatic secretions (EPS) and the concentration of citric acid in patients with chronic prostatitis. Materials and Methods: The study involved 34 men with chronic prostatitis. The leukocyte count, presence of anti-C.t. antibodies (IgA, IgG), and citric acid concentration were determined in the EPS. The serum was examined for IgM, IgA, and IgG anti-C.t. antibodies. Specific antibodies were determined using the EIA method. The concentration of citric acid was measured using the ultraviolet method. Results: Inflammation of the prostate (10 PMN) was found in 61.8% of the patients. A reduction in citric acid concentration in the EPS was detected in 58.8% of the men. Specific serum antibodies were detected in 58.8% of the patients, including 23.5% with IgM, 32.4% with IgA, and 44.1% with IgG. In all patients, serum IgM and IgA antibody titers were low, while those of IgG antibodies were strongly positive in 46.7% of the patients. Anti-C.t. antibodies in the EPS were detected in 44.1% of the patients, including 32.4% with IgA and 35.3% with IgG. In contrast to serum, the titers of IgG antibodies in the EPS were low in all the patients, while those of IgA were strongly positive in 54.5% of cases. In patients with positive serological outcomes, 85% had reduced concentrations of citric acid.Conclusions: The occurrence of anti-C.t. antibodies is usually accompanied by a decrease in the concentration of citric acid in the prostatic secretion.