OBJECTIVE: ANCA (p-ANCA and x-ANCA) have been documented to occur in many inflammatory disorders. The specific ANCA antigens and the clinical correlation of a positive ANCA test in these disorders are still for the most part obscure. The aim of the present study was to investigate the prevalence of and the target antigens for ANCA in patients with IBD. METHODS: 104 patients (67 age between 3-18 years, mean age 8+/-3 and 37 age between 25-70 years, mean age 48+/-15) clinically and hystopathologically diagnosed as: 67 ulcerative colitis, 16 Crohn' disease, 21 other colitis (7 indeterminate colitis) were enrolled in our study. ANCA were determined by ELISA and IIF methods. RESULTS: We observed a good performance in terms of sensibility and specificity of ANCA, and a good correlation between the two methods used; as regard ELISA determination the antigen frequently found in our cases was lactoferrin (60%). CONCLUSIONS: Is still unclear the role of these "minor antigens" in the diagnosis and pathogenesis of IBD, but is clear that only morphologic evaluation is no more sufficient.