In SLE, scleroderma, and PM/DM, infections are important causes of morbidity and mortality. This increased risk of developing infections is the result of immune abnormalities and of organ system manifestations associated with these diseases and their treatments. Common bacteria are responsible for most mild and lethal infections; however, opportunistic microorganisms cause death in some patients, particularly in those receiving high doses of corticosteroid and immunosuppressive therapy. Various viral and fungal infections also contribute to the morbidity and mortality associated with these diseases. Regardless of the cause of infections, adequate and prompt recognition and proper treatment of the infected patient are imperative. Thus, patients with these diseases, especially when receiving high doses of corticosteroids and immunosuppressive therapy, need to be monitored closely for these infections. This care and concern is necessary to ensure optimal patient outcomes, both in terms of morbidity and mortality.