Aim: To evaluate the clinical significance of the quantitative determinations of endotoxins in the expressed prostatic secretions (EPS) of chronic prostatitis (CP) patients. Methods: The EPS of 45 patients with CP and 15 normal volunteers were obtained for microscopic examination, bacterial culture and endotoxin determination. The level of endotoxins was determined by the Limulus-amebocyte-lysate test with chromogenic substrate. Results: Patients (P＞0.05), type Ⅱ/type Ⅲa vs. Normal controls P ＜ 0.05)]. Conclusion: CP patients have elevated levels of endotoxins in the EPS, which suggests that inflammation is a feature of this disease. EPS endotoxin determination is not only helpful in diagnostic confirmation, but also in evaluating the response to treatment in CP patients.