Background: In some hospitals, urinalysis is done routinely for all patients scheduled for cardiac surgery. Occasionally pyuria or bacteria is reported in the microscopic urinalysis of these patients that are clinically asymptomatic for urinary tract infections.Objectives: WE WERE SEEKING ANSWER TO THIS QUESTION: is the presence of a different number of bacteria in preoperative microscopic urinalysis of asymptomatic patients scheduled for cardiac surgery indicative of potential postoperative complications and as a result, a good reason to postpone the operation?Patients And Methods: We conducted a retrospective cross-sectional study based on the review of the medical records of 1165 patients who underwent open-heart surgery.