Hydroxychloroquine (HCQ) is by far the most frequently used antimalarial for the management of Systemic Autoimmune Diseases. It has immunomodulatory, hypolipidemic, hypoglycemic and antithrombotic properties and it diminishes the risk of malignancies. The most important mechanisms to explain the immunomodulatory actions are its ability to reduce inflammatory pathways and Toll-like receptors activation. The safety profile is favorable. In spite of its low frequency, retinal toxicity is potentially severe. In systemic lupus erythematous HCQ therapy reduces activity, the accrual of organ damage, risk of infections and thrombosis and improves the cardiometabolic profile. It contributes to induce lupus nephritis remission, spares steroid use and increases survival rates. In rheumatoid arthritis, it improves cardiometabolic risk and has a favorable effect in joint inflammation. In Sjögren’s syndrome, an increased lacrimal quality as well as an improvement in objective and subjective inflammatory markers has been demonstrated with HCQ. In Antiphospholipid Syndrome, HCQ is effective in primary and secondary thrombosis prevention. The effectiveness of the drug in other systemic autoimmune diseases is less established. HCQ therapy may improve dermatological manifestations in Dermatomyositis and may have a positive effects in the treatment of Sarcoidosis and Still disease.Hydroxychloroquine (HCQ) is by far the most frequently used antimalarial for the management of Systemic Autoimmune Diseases. It has immunomodulatory, hypolipidemic, hypoglycemic and antithrombotic properties and it diminishes the risk of malignancies. The most important mechanisms to explain the immunomodulatory actions are its ability to reduce inflammatory pathways and Toll-like receptors activation. The safety profile is favorable. In spite of its low frequency, retinal toxicity is potentially severe. In systemic lupus erythematous HCQ therapy reduces activity, the accrual of organ damage, risk of infections and thrombosis and improves the cardiometabolic profile. It contributes to induce lupus nephritis remission, spares steroid use and increases survival rates. In rheumatoid arthritis, it improves cardiometabolic risk and has a favorable effect in joint inflammation. In Sjögren’s syndrome, an increased lacrimal quality as well as an improvement in objective and subjective inflammatory markers has been demonstrated with HCQ. In Antiphospholipid Syndrome, HCQ is effective in primary and secondary thrombosis prevention. The effectiveness of the drug in other systemic autoimmune diseases is less established. HCQ therapy may improve dermatological manifestations in Dermatomyositis and may have a positive effects in the treatment of Sarcoidosis and Still disease.