Tumor necrosis factor (TNF-alpha) is a cytokine which can be found in peritoneal fluid (PF) of patients with endometriosis and pelvic inflammatory disease (PID) as a response of inflammatory disorder and infections diseases. The cytotoxic effect of this cytokine could be participating in the pathology of different gynecologic problem and be accountable of the high immunological response and damage on the tubal epithelium. The objective of this study was determinate the presence of TNF-alpha in PF of endometriosis patients, fallopian tube occlusion (FTO) and PID and their correlation with different isolated bacteria. Ten mililiter PF were collected and cultured in antificial medium and Mc Coy culture cells for isolation of acrobic, and anaerobic bacteria and Chlamydia trachomatis from 73 patients by laparoscopy. The TNF-alpha activity was determined by L-929 cells endometriosis, 30 PID and 4 had miomas and adherences. The 50.7% of patients were cultive positive, fom these, 31.5% were PID. Chlamydia trachomatis (16%) was the most frecuenty isolated bacteria in these patients. 59.4% of FTO patients displayed TNF-alpha activity. However, only 4% showed positive isolation, in conclusion the detection of TNF-alpha could be useful in active infectious and inflammatory diseases in patients which not present simptomatologic characteristic of these illnesses and plus being attended at for sterility clinical as a result of their incapacity to get pregnant.