Microparticles (MPs) are membrane-bound vesicles that can act as unique signaling elements in the pathogenesis of rheumatic diseases. MPs originating from platelets, leukocytes, endothelial cells and erythrocytes are found in circulating blood at relative concentrations determined by pathophysiological context. Once released from cells by membrane blebbing, MPs display diverse functional activities and can mediate intercellular communication. Importantly, in the context of rheumatic diseases, MPs can regulate thrombosis, vascular reactivity, angiogenesis and inflammation. Consistent with the role of MPs in immunopathogenesis, patients with rheumatic diseases show marked increase in the number of particles in the blood, which can reflect the extent and severity of the diseases. MPs are now emerging as new biomarkers from a specific tissue undergoing activation or damage. Thus detection of MPs in the circulating blood, would not only improve our comprehension of disease pathogenesis, but also constitute a powerful tool as a biomarker in the prediction, diagnosis, prognosis and follow up of rheumatic diseases.