Abstract: Pyuria is the presence of increased numbers of polymorphonuclear leukocytes in the urine and is evidence of an inflammatory response in the Urinary Tract Infection (UTI). The aim of this study is determination asymptomatic bacteriuria and pyuria in patients undergoing hemodialysis with chronic renal failure. Out of 103 patients with renal failure undergoing hemodialysis who were able to produce urine with clean catch way, we received urine sample. All samples were examined by the Microbiologist in Central Laboratory of Kermanshah, Iran. The mean age for the patients at diagnosis was 42.4 years (range, 20-67 years). Sixty-four patients (62.5%) were male and thirty-nine (37.5%) were female. Results have been showed 39 cases were aged between 44-49 years and the highest number cases were middle-aged. Out of 31 patients with leukocytosis, 14 patients had age between 44-49 years and majority of them were male. Pyuria(>10 WBC/HPF or <10 WBC/HPF) was more in male that had between 40-49 years. Patients (10/12) with pyuria (>10 WBC/HPF) developed colony count more than 105 colony-forming units per milliliter that indicating positive culture. Microorganisms didn’t grow in patients (10/19) with pyuria (<10 WBC/HPF). This study demonstrates that the UTI, even in end stage renal disease (ESRD) patients on hemodialysis, may represent a significant reservoir for infection and pyuria >10 WBC/HPF is a good marker for significant bacteriuria in these patients.