There are few reports about the coexistence of Sjögren's syndrome (SS) and ankylosing spondylitis (AS). To evaluate the frequency of SS in patients with AS. We studied 70 patients with AS presenting to the university outpatient clinic between January 2002 and November 2003. All the patients were asked about sicca symptoms by using sicca questionnaire. Rheumatoid factor, anti-nuclear antibody, anti-Ro, and anti-La antibodies were examined for each of the patients. Salivary flowmetry for the existence of xerostomia, Schirmer's test, and break-up time for the existence of xerophtalmia were performed in all patients with AS. Minor salivary gland biopsy was performed on the patients with at least three positive responses to the sicca questionnaire and positive xerostomia/xerophtalmia tests. Biopsies were regarded as pathological when they showed focal grade iii and grade IV sialoadenitis according to Chisholm grading criteria. Among 70 AS cases, 56 (80%) were men, 14 (20%) were women, and the mean age was 42 years old. Minor salivary gland biopsy was performed on the 16 patients. Of 16 minor salivary gland biopsies, 7 were assessed as pathological--5 of them showed grade III, and 2 of them showed grade IV sialoadenitis. Of these seven patients, one was anti-Ro-positive, and two were anti-La-positive. There was no patient with normal salivary gland biopsy and anti-Ro and/or anti-La positivity. In our study group, 7 (10%) of 70 AS patients had concomitant SS. Therefore, it seems likely that AS may have pathogenetic association with SS.