Objective To investigate mechanism of chronic bacterial prostatitis (CBP) causes increased oxidative stress and oxidative damage in the patients. Methods Seventy CBP patients (CBPPs) sampled randomly, and seventy healthy adult volunteers(HAVs) sampled randomly, were enrolled in a case-control study, in which the levels of nitric oxide (NO), vitamin C (VC), vitamin E (VE), and (-carotene ((-CAR) in plasma, as well as the level of malondialdehyde (MDA), and the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) in erythrocytes were determined by spectrophotometry. Results Compared with the average values of NO and MDA in the HAVs group((378?33)nmol/L和(28.6?4.4)nmol/g?Hb),the average values in the CBPPs group ((426?31)nmol/L and (34.7?4.7)nmol/g?Hb)were significantly increased, while VC, VE, ?-CAR, SOD, CAT, and GPX in the CBPPs group((47.4?11.6)?mol/L,(18.1?4.8)?mol/L,(1.4?0.4)?mol/L, (1 912?221)U/g?Hb, (254?67) K/g?Hb and (25.0?5.0) U/g?Hb) were significantly decreased compared with the average values in the HAVs group((55.1?13.4)?mol/L、(25.7?4.5)?mol/L、(1.7?0.5)?mol/L、(2 081?222)U/g?Hb、(294?77)K/g?Hb和(28.8?5.1)U/g?Hb)).The partial correlation analysis between the course of disease and the said each parameter for 70 CBPPs while controlling for the age suggested that with prolonged course of disease the values of NO and MDA were gradually increased (rNO=0.480 1,rMDA=0.436 4,P