Objective:To investigate whether different type of chronic prostatitis could have a deleterious effect on semen quality. Methods: Forty-nine patients diagnosed as suffering from chronic prostatitis were included and di-vided into groups according to the presence of infection and/or cellular autoimmune response against prostate anti-gens. Healthy normal individuals were included as controls. Measurements for sperm concentration, motility, morphology, prostate and seminal vesicle markers, antisperm antibodies, white blood cells and pro-inflammatory cytokines were performed accordingly. Results:The most severe abnormalities were found in patients with no evi-dent infection and an autoimmune response against prostate antigens. Moreover, significantly increased levels of pro-inflammatory cytokines were detected in seminal plasma from these patients. Conclusions: This study shows that chronic prostatitis patients with cellular autoimmune response to prostate antigens present important altera-tions in their semen quality parameters and may affect male fertility.