The study was carried out to determine clinical and immunologic predictors of unfavorable variant of course of ulcer colitis. The sample included 89 patients (48 females--53.9% and 41 males--46.1%) with ulcer colitis established on the basis of clinical, endoscopic and morphologic data. The age of patients was 18-79 years and mean age--42.49 +/- 1.61 years. The patients were divided on two groups depending on clinical course of disease: group 1 with favorable course and group 2 with unfavorable course. The group 2 included patients with frequently relapsing form of disease, patients with hormone-depended/hormone-resistant form of disease and patients with severe exacerbation ua ulcer colitis at the moment of examination. The groups were compared by gender and age. All patients underwent medical history and complaints acquisition and total clinical examination. The clinical and biochemical analysis of blood was made too. The severity of disease was established using the calculation of Trulove- Witts indicator The anti-neutrophil cytoplasmic antibodies of classes IgG and IgA were analyzed using indirect immunofluorescence (Euroimmun AG, Germany). The diagnostic anti-neutrophil cytoplasmic antibodies titer was established in 58 out of 87 of examined patients (66.6%). The antineutrophil cytoplasmic antibodies of class IgG was revealed in 42 patients and anti-neutrophil cytoplasmic antibodies of class IgA in 27 patients. The combination of both classes of anti-neutrophil cytoplasmic antibodies was established in 11 examined patients. In the group of favorable course of disease the diagnostic titer of anti-neutrophil cytoplasmic antibodies was revealed in 20 patients (51%). At the same time, in the subgroups with frequently relapsing, hormone-depended/hormone-resistant and severe forms of disease these antibodies were revealed with rate of 76, 77 and 86.3% correspondingly. Hence, the anti-neutrophil cytoplasmic antibodies can be used both in diagnostic of ulcer colitis and in prognosis of course of disease.