The presence of anti-neutrophil cytoplasmic autoantibodies is a diagnostic marker for many vascular diseases. Antibodies against myeloperoidase can occur in vasculitis, glomerulonephritis, poliarteritis nodosa, Churg-Strauss syndrome, systemic lupus erythematosus, rheumatoid arthritis. Antibodies against proteinase-3 can support the diagnosis of Wegener' s Granulomatosis. It is possible to detect these antibodies by ELISA (enzyme linked immunosorbent assay) and IIFA(indirect immunofluroscence assay) methods and by electron microscope technics. In this study, serum samples (from 88 female and 49 male) of 137 patients who were prediagnosed for various inflammatory diseases, were evaluated. As a result we think that an ELISA test including two major antigens like myeloperoxidase and proteinase-3 can be a useful screening test.