Ultrasonographic (US) evaluation of the moving shoulder is a new method for evaluating the integrity of the rotator cuff. In the past, contrast arthrography has provided the only nonoperative technique for demonstrating defects in the rotator cuff. We present the details of this new technique and describe 79 patients whose US results were correlated with the findings at arthrography and/or surgery. US allows evaluation of both shoulders at once, an advantage over arthrography, where usually only one side is evaluated at a single sitting. Improvements in US instrumentation, especially the introduction of high-resolution linear-array devices and the use of experienced ultrasonographers, have improved the accuracy of US. Because US is rapid, safe, noninvasive, and inexpensive, we advocate its use instead of arthrography as the routine test of rotator cuff integrity.