The presence of antineutrophil cytoplasmic antibodies (ANCA) and their specificity to myeloperoxidase, lactoferrin and elastase were studied in 27 patients with thromboangiitis obliterans (Buerger's disease), including nine in mild stage of the disease (group I) and 18 in active or severe stage (group II). Serum samples were investigated for ANCA prevalence by indirect immunofluorescent technique and fixed neutrophil ELISA; the reactivity to myeloperoxidase, lactoferrin and elastase was measured by ELISA. ANCA were found in 55.5% (15/27) of the patients by indirect immunofluorescence and in 59.25% (16/27) by fixed neutrophil ELISA. A highly significant positive association was observed between the values obtained by the two methods. Only six of 15 ANCA-positive sera reacted with myeloperoxidase and four of 15 with lactoferrin. One ANCA-negative serum reacted with elastase. Antimyeloperoxidase, antilactoferrin and antielastase autoantibodies were found only in the severe group. There was statistically significant difference in the frequency of ANCA in sera of patients with thromboangiitis obliterans versus control sera. ANCA were predominantly found in group II (66.7%; 12/18) compared to group I (33.3%; 3/9) and the levels of antimyeloperoxidase, antilactoferrin and antielastase antibodies correlated with disease severity. Therefore, detection of ANCA can be a helpful serological test for the diagnosis of thromboangiitis obliterans.