OZ SUMMARY THE PREVALENCE OF IRRITABLE BOWEL SYNDROME IN PATIENTS WITH ANKYLOSING SPONDYLITIS Objective: Irritable bowel syndrome (IBS) is a functional bowel disease, characterized by altered bowel habits and chronic abdominal pain. IBS has an increased association with inflammatory pathologies such as rheumatoid arthritis (RA), but the role of inflammation in the pathophysiology of IBS hasn’t been clarified yet. Ankylosing spondylitis (AS) is a chronic inflammatory disease of the axial skeleton. The aim of our study is to determine the frequency of IBS in AS, and to reveal its relationship with other factors, primarily with disease activity. Material and Method: 145 patients with AS in the rheumatology clinic of Namik Kemal University were included. Along with demographic, clinical and laboratory data of the patients, disease activity and biologic drug use were recorded. The diagnosis and type of IBS were examined according to ROME III criteria. Results: The prevalence of IBS in patients with AS was 31.7%. Frequency of IBS was significantly higher in higher disease activity group (BASDAI>4) and in patients treated with biological agents (p values 4) ve biyolojik ajan tedavisi alanlarda anlamli sekilde yuksekti (p<0.001 ve p: 0.01 sirasiyla). Cinsiyetler arasinda IBS kadin hastalarda, yasa gore ise genc hastalarda (<50 yas) anlamli sekilde yuksekti (p: 0.012 ve p<0.01 sirasiyla). Sonuc: IBS; AS hastalarinda normal populasyona kiyasla daha yuksek (%31.7) tespit edildi. AS hastalik aktivite skoru ile IBS arasindaki iliski patogenezde inflamasyonun etkisini dusundurdu. Sonuc olarak ozellikle hastalik aktivitesi yuksek olan AS hastalarinda gastroenterolojik sikayetler sorgulanmali, sik bir komorbidite olan IBS takip surecinde goz ardi edilmemelidir.