Type I interferons (IFN) are primarily regarded as an inhibitor of viral replication. However, type I IFN, mainly IFNα, has a major role in activation of both the innate and adaptive immune systems. Systemic lupus erythematosus (SLE) is a chronic, multi-systemic, inflammatory autoimmune disease with undefined etiology. SLE is characterized by dysregulation of both the innate and the adaptive immune systems. An increased expression of type I IFN-regulated genes, termed IFN signature, has been reported in patients with SLE. We review here the role of IFNα in the pathogenesis and course of SLE and the possible role of IFNα inhibition as a novel treatment for lupus patients.