Rheumatic manifestations are the most common extraintestinal findings of inflammatory bowel disease (IBD), although there are wide variations among different studies. The only previous Turkish study reported a rather high prevalence of spondyloarthritis (SpA) in patients with IBD. We aimed to determine the frequency of SpA and ankylosing spondylitis (AS) in patients with IBD attending a gastroenterology clinic from a referral centre. The study was conducted in 122 patients with established diagnosis of IBD [28 with Crohn's disease (CD) and 94 with ulcerative colitis (UC)]. A detailed medical history was obtained and a complete physical examination was performed in all the patients. Standard pelvic X-rays for examination of the sacroiliac joints were performed only when clinically indicated. The X-rays were read blindly by an experienced rheumatologist and reported according to the established grading system. The modified New York criteria were used to classify AS, and the European Spondyloarthropathy Study Group criteria for SpA. The prevalence of AS and SpA in patients with IBD was 8.2 and 28.7%, respectively. SpA was found to be significantly more common in the patients with CD compared to patients with UC, but the frequency of AS was not different between these two groups. There was no correlation between localisation or extent of the intestinal inflammation and presence of AS and SpA. A higher frequency of women was observed in patients diagnosed as SpA. Almost half of the patients with SpA (45.7%) had not been diagnosed before the study, although they had a history of IBP and/or peripheral arthritis. This study suggests that the prevalences of SpA and AS in Turkish patients with IBD are similar to those in many other populations. There may be a significant female predominance of SpA among patients with IBD.