Objectives: To identify bacterial species present in the lower genital tract of males and to investigate the relationship with semen quality and male infertility. Methods: The microscopic analyses, cultures and ELISA technique of 175 semen and serum specimens, collected over 9 months from males investigated for infertility, were prospectively assessed. Results: One hundred and seventy five seminal fluid, blood and serum specimens were collected from men investigated for infertility over a period of 9 months (from April 2011 to December 2011) were analyzed. The seminal fluids and serum of patients mentioned to the laboratory from the fertility clinics of Babylon maternity and children Hospital and outer clinics. The results had shown that from 17 microbial species there are, Ureaplasma urealyticum 4.938272 %, Ureaplasma parvum 2.160494 %, Mycoplasma hominis 2.469136 %, Mycoplasma genetalium 5.864198 %, Chlamydia trachomatis 9.876543 %, Streptococcus pyogenes 8.641975 % , Staphylococcus aureus 11.11111 %, Staphylococcus epidermidis 12.03704 %, Staphylococcus saprophyticus 0.925926 %, Escherichia coli 20.06173 %, Proteus mirabilis 1.234568 %, Proteus vulgaris 2.469136 %, Klebsiella pneumoniae 0.925926 %, Pseudomonas aeuroginosa 1.54321 %, Neisseria gonorrhoeae 2.777778 %, Toxoplasma gondii 6.17284 % and Candida 6.790123 %. Also the infection with microorganisms revealed that it is higher in azoospermic patients than normospermic group (control). Keywords: Male infertility, ELISA technique, Bacterial infection