Urinalysis is the most convenient and important diagnostic tool for the kidney diseases. Abnormal urinary findings provide powerful information for the diagnosis of a kidney disease. There are several common urinary abnormalities without subjective symptoms : hematuria, proteinuria, and asymptomatic bacteriuria. There are many causes of hematuria : glomerulonephritis, interstitial nephritis, vascular diseases, cystic kidney disease, renal calculi, coagulation disorders, urinary tract infection, trauma, and tumors. It is essential to clarify the origin of hematuria by the use of diagnostic flow sheets. Despite all the diagnostic approaches, however, unexplained hematuria is found in 10~15% of subjects with hematuria. Periodic follow-up is recommended per 3 to 6 months for at least three years for them. The proteinuria of the glomerular origin is important for the progression of the renal diseases. We have to differentiate the proteinuria according to its origin and underlying systemic diseases including diabetes mellitus and hypertension. We also recommend a kidney biopsy for nephrotic range proteinuria for the diagnosis, treatment, and prognosis of the disease. Asymptomatic bacteriuria is define as a bacterial colony count above 105/ml in two consecutive urine cultures. Management is generally not recommended for the asymptomatic bacteriuria in elderly patients but recommended in pregnant women and diabetes mellitus patients. From our point of view, subjects showing urinary abnormalities, such as hematuria, proteinuria, and bacteriuria, must be kept under close surveillance.