The detection of microscopic hematuria on routine urinalysis in a patient with no urological symptoms presents the urologist with a management dilemma. Many authors1-6 have recommended intravenous pyelography (IVP) or renal ultrasound, and cystourethroscopy as the minimum investigation in all patients with this finding. While recognizing that microscopic hematuria may represent an early sign of a life threatening but curable urological cancer, urologists are also aware that a full urological investigation in most of these patients will not detect a life-threatening lesion. Under these circumstances, it is understandable that the urologist may be reluctant to subject every patient asymptomatic microscopic hematuria to an IVP and cystourethroscopy. Factors that may influence the urologist include the recognition that a certain number of erythrocytes (RBCs) in the urine may be accepted as within normal limits, and associated elements in the urine such as protein, or red cell or granular casts suggest a glomerular as opposed to a urological cause for the hematuria. The purpose of this review is to clarify our understanding of the normal limits of microscopic hematuria, to review recently introduced techiniques that may be helpful in determining that the hematuria is of glomerular origin, and to examine the data on which recommendations for patients investigation is advisable, it is necessary to address the question of which investigation are most appropriate, and whether under any circumstances, any investigations can be safely omitted.