Abstract INTRODUCTION: Cardiovascular disease is the main cause of mortality in developing countries. Because the major classic risk factors fail to explain the disease's epidemiologic diversity, other risk factors such as inflammation and systemic infections are being investigated, although no cause and effect relation between these infections and acute coronary syndrome (ACS) has yet been decisively proven. In view of the possible role of local and systemic infections in the occurrence of ACS, as well as leukocyturia and hematuria, the present study was designed and carried out. methods: This was a prospective case-control study of all patients diagnosed as having ACS and hospitalized at the CCU of Fatemiyeh Hospital in Semnan. Urine analysis and culture were performed in all patients and the control group in the early stage of admission to the CCU. After collecting data, we examined the associations and the differences between the two groups by using t-test and chi-square test. results: The case and control groups did not show any significant difference based on age and sex (age 60.03±19.32 years in cases and 59.9±17.2 years in controls, female prevalence was 40.5% in both groups). Hematuria was seen in 18.5% of cases and 5% of controls (P<0.0001). Leukocyturia was seen in 28.5% of cases and 12% of controls (P<0.0001). Albuminuria was seen in 6% of cases and 7% of controls (P>0.05). CONCLUSIONS: These findings indicated the presence of sub-clinical underlying infection process due to uncommon pathogens or leukocyturia and hematuria in a systemic inflammatory process that can predispose to ACS by systemic inflammation.   Keywords: Hematuria, leukocyturia, acute coronary syndrome.