The normal anatomy of the long head of the biceps tendon of the shoulder has been described in detail [1]. Descriptions of different pathologic processes affecting this structure also have been published [1-3] but have been incomplete, showing only a limited variety of abnormalities. In this article, abnormalities of the long head of the biceps tendon seen on MR images are illustrated in greater variety and detail. Recognizing abnormalities of the biceps tendon is important because they are a common source of shoulder pain both alone and in combination with abnormalities of the rotator cuff, labrum, and other structures. Because incomplete diagnosis can lead to treatment failure, it is important to recognize less common imaging manifestations of common entities.