The relation between rheumatic syndromes and an underlying malignancy is a complex one. As a result of autoimmunity, an aberrant immune response, or the use of immunomodulatory drugs, many of the rheumatic diseases appear to pose an increased risk for the development of malignancy. Unfortunately, for many of the same reasons, the presence of an underlying malignancy can result in the development of features of rheumatic disease. Awareness of the associations between rheumatic syndromes and malignancy will aid the clinician in the accurate diagnosis of underlying pathology, more effective treatment of both the symptoms and underlying disease, and appropriate surveillance for the development of later complications.