This article examines the role of sonohysterography as an extension of the transvaginal ultrasound examination. This technique is used to improve visualization of the endometrial cavity and its relationship to the uterus. The authors find that it is well tolerated and causes few complications. The improved anatomic resolution increases diagnostic confidence and helps direct the patient to appropriate therapeutic options, potentially decreasing the need for more costly or invasive examinations. The addition of three-dimensional ultrasound makes the examination quicker and expands the utility of the procedure. The authors conclude that it will play a growing role in the evaluation of common gynecologic problems and in defining uterine pathology.