Ultrasonography of the urinary bladder has evolved with improvements in ultrasound instrumentation. The bladder may be visualized transabdominally, transurethrally, and transrectally. Bladder tumors may be accurately staged. Postvoiding residual urine may be measured accurately and noninvasively. As newer indications are evaluated, including ultrasound imaging of the bladder during urodynamic studies, ultrasound of the bladder will be performed more readily by urologists.