Benign masses outnumber sarcomas. The use of MR imaging for the indeterminate soft-tissue mass has during the past decade permitted radiologists to name the soft-tissue mass or provide a succinct differential diagnosis. This article reviews the identification of benign masses based on signal intensity, location, morphologic characteristics, and other features. The importance of approaching every "indeterminate" mass after MR imaging as malignant until proved otherwise is emphasized, as is the fact that despite the accessibility of the mass, a biopsy should not be done without prior consultation with an orthopedic oncologist.