The immunologic cardiovascular diseases are a heterogeneous group of conditions. Many of these entities are associated with serious morbidity and mortality resulting from cardiac impairment, ischemic complications, or organ dysfunction, particularly of the kidneys, lung, and nervous system. The systemic nature of these conditions, coupled with vague symptoms and nonspecific initial physical findings, makes the differential diagnosis complicated. Research has identified specific mediators and primary origins in some conditions, with infections often being responsible. Immunosuppressive therapy, despite the potential complications, has improved the prognosis of some of the more serious immunologic cardiovascular diseases. Improvement in the treatment of immunologic cardiovascular diseases awaits identification of additional causes, improved definition of host factors that predispose an individual to develop these conditions, and better understanding of the immune dysregulation responsible for the progression of disease. The potential pathophysiologic role of immunologic mechanisms in common disorders such as congestive heart failure and atherosclerosis is intriguing and offers the possibility of novel therapies in these prevalent conditions.