The emergency physician can expect to commonly evaluate patients with hematuria, and the differential diagnosis will include both benign and life-threatening causes. This differential is divided into the following categories: glomerular or nonglomerular, coagulopathy-related, traumatic, and factitious causes. Nonglomerular causes account for the majority of hematuria evaluated in the ED, with infection and stones being the most prevalent diagnoses. Glomerular causes will have associated red cell casts and proteinuria present on urinalysis. Painless atraumatic gross hematuria in the elderly is caused by a malignancy until proven otherwise. A focused history, physical exam, and appropriate diagnostic testing in the ED usually yields a diagnosis. If the patient is discharged home, proper follow-up with the primary care physician, urologist, or nephrologist is indicated, depending upon the diagnosis.