Systemic lupus erythematosus (SLE) is characterized by multisystem inflammation and production of autoantibodies, which can generate immune complexes and may cause tissue damage through the recognition of an autoantigen. Although many factors have been proposed, such as genetic factors, environmental factors, hormonal action, viruses, and dysregulation of cytokine production, the cause of this disease is not well understood. It has been reported that the levels of interferon (IFN)-alpha in the sera of some SLE patients are elevated and that IFN-alpha induces maturation of monocytes into highly active antigen-presenting dendritic cells (DCs). We analyzed the association between IFN-alpha genotype and the risk of SLE to clarify whether IFN-alpha plays a central role in susceptibility to SLE. The results showed that no IFN-alpha genotype was significantly associated with the risk of SLE.