Recently ultrasound has been used to size and track individual myoma volumes for patients undergoing medical therapy. However, little is known about the specific performance characteristics and limitations of this technique with respect to volume measurements. We performed and prospectively interpreted serial ultrasound examinations on myoma patients and confirmed the location, size and number of myomas in the surgical specimens. The smallest detectable tumor was 2.7 cm in diameter. The specificity was 94%; reproducibility had a 14% coefficient of variation for tumors with diameters greater than 6 cm. We conclude that ultrasound is suitable for imaging and sizing myomas provided that the diagnosis is otherwise certain and the tumors tracked are large.