Ankylosing spondylitis (AS) is an inflammatory disease which involves especially columna vertebralis. There is commonly noted restrictive pulmonary disease due to involvement of the thoracic joints, therefore it results in decreased vital capacity. The aim of this study is to assess the cardiovascular endurance in AS patients by an indirect test (Astrand test) and to investigate the relationship between thoracic expansion range and vital capacity. Twenty one patients with AS were recruited in the study. Astrand test was performed only in 17 of this patients with simultaneous assessment of thoracic expansion range and vital capacity. Patients were questioned about smoking habits and Pearson correlation and Student-t test were used for statistical analysis. This study group were composed of 2 females and 15 males with mean 30± 7years of ages. The mean disease duration was 72 ±75 months. There was no correlation between VO2 max with thoracic expansion range, vital capacity and disease duration (p>0.05). There was no significant difference ofVO2max values in smoking and nonsmoking patients (p>0.05). VO2max may not show any significant decrease, because our patients were mostly males and actively working people. Furthermore we hypothesized that the lack of correlation may be due to the slow progression of disease. As a result, we state that we have not found a significant correlation between thoracic expansion range, vital capacity and cardiovascular endurance in our series and we believe that cardiovascular endurance may be affected by various other factors, and larger randomized controlled studies are needed to confirm these results.