The aim of the study was to evaluate early efficacy of anti-TNF treatment in patients with active ankylosing spondylitis (AS). The patients included in the observation were 10 women and 24 men, mean age 39 years, mean disease duration 13 years, who had been qualified for anti-TNF treatment in the therapeutic programme of the National Health Service (Table I). Qualification criteria included: AS diagnosis according to Modified New York Criteria, active disease ascertained at least two times in the 12-month period in terms of stable treatment, and inefficacy of at least two nonsteroid anti-inflammatory drugs used in maximum tolerant doses, each of them taken for minimum 3 months. Nineteen of the patients were treated with etanercept and 15 with adalimumab. The treatment efficacy was evaluated monthly using complex indices of disease activity (BASDAI, ASDAS), functional ability (BASMI, BASFI) and quality of life questionnaire (ASQol) (Table II). After 12 weeks most of the patients improved according to BASDAI 50 index (equal with 20% ASAS improvement). Forty and sixty percent ASAS improvement was observed in 88.2% and 52.9% of patients, respectively (Figure 1–3). We have not found any significant differences in the effectiveness of treatment in terms of the disease duration and activity as well as the anti-TNF molecule used. The patients with a high serum CRP level at baseline experienced better improvement according to BASDAI and ASDAS indices than the patients with CRP within normal limits. Statistically significant improvement in terms of inflammatory indicators (ESR, CRP) was accomplished during the first 4 weeks of treatment, whereas those indicators did not improve significantly during the following 8 weeks. The improvement, measured according to complex disease activity indices (BASDAI i ASDAS), global patients’ and doctors’ assessment, as well as functional and quality of life indices (BASMI, BASFI i ASQol) was progressing almost linearly during 12 weeks of the treatment (Figure 4, 5).