Abstract SLE is a chronic, recurrent, potentially fatal multisystem inflammatory disorder mainly affecting women. SLE patients produce antibodies to many different self-antigens. Yet, currently used serological markers for SLE are lacking in specificity and/or sensitivity. The aim of this study was to develop an improved diagnostic test by measuring and multiplexing specific autoantibody reactivities in SLE patients. Autoantibody reactivity profiles in serum samples collected from 97 SLE patients within three years of the diagnosis were compared with those of 56 healthy controls. Autoantibody profiles were determined using the ImmunArray iCHIP™ - a proprietary protein microarray technology that allows the display of antigens representing a wide range of SLE-associated biochemical pathways on a single chip. Using this novel platform, SLE patients could be differentiated from healthy subjects by a relatively small subset of auto-antigens and Epstein Barr Virus (EBV) antigens. The autoantibody reactivity profile that allowed SLE diagnosis with high sensitivity and specificity displayed differential response to known SLE-specific antigens, such as single-stranded DNA and EBV, and to several novel ones. Conclusion: An antibody profile for SLE diagnosis using a single multiplexed chip was successfully developed. This profile may differentiate between SLE patients and healthy individuals. Validation of this profile in additional patient samples is ongoing.