Patients with systemic autoimmune rheumatic diseases, particularly RA, SLE, SS and idiopathic inflammatory myopathies, are at increased risk of developing malignancies. Cancer occurrence adds to the disease burden in these patients, adversely affecting quality of life and life expectancy. This risk is related to the pathobiology of the underlying rheumatic disease including the inflammatory burden, immunological defects, and personal and environmental exposure such as smoking and some viral infections. Immunomodulatory therapies, especially chemotherapeutic agents, are also associated with an increased risk of cancer in these conditions. The decision to use immunomodulating therapies in patients with rheumatic disease must take into account the disease severity, expectations for disease control, comorbidities and host and environmental risk factors for cancer. Effective screening and monitoring strategies are important in reducing the risk of cancer in these patients.