Although hematuria is a common finding in the unselected population of children, the approach to evaluation is quite variable. Changes in the practice of primary care medicine in the United States mandate an approach to common office problems that is practical and realistic. This review addresses three areas: the current approach to evaluation of hematuria in children, a classification of children with hematuria into four distinct and easily identified clinical categories, and the development of an algorithm for application in the primary care setting. Each category is discussed relative to the more-common etiologies of hematuria, with recommendations for appropriate evaluation as well as suggestions of an appropriate referral to the nephrologist. An algorithm is proposed that provides a practical, systematic approach to the problem without the requirement for a specific diagnosis in every patient. The proposed classification and approach to the evaluation of children with hematuria should help simplify and clarify a potentially complex process.