Objective: Human leukocyte antigen B27 (HLA-B27) is strongly associated with ankylosing spondylitis (AS). However, the association between clinical findings and HLA-B27 vary in terms of geographic area. This study aimed to determine the frequency of HLA-B27 positivity and its relationship with clinical findings. Material and Methods: All subjects fulfilling the modified New York diagnosis criteria for AS enrolled in study. The demographic data and histories of the patients were collected retrospectively from patient files. Polymerase chain reaction-based HLA-B27 analysis of all cases was performed.Results: The male to female ratio was 2.5, and mean age of disease onset was 28.3 years. HLA-B27 positivity was detected in 115 patients (70%). Although there was no significant connection between the clinical findings and HLA-B27 positivity, there was a positive relationship between the presence of syndesmophytes and HLA-B27 positivity (p=0.044). The number of patients treated with anti-tumor necrosis factor was higher in the HLA-B27-positive group; however, the difference was not significant (39.1% and 28.9%, respectively). More patients were treated with anti-tumor necrosis factor in the HLA-B27-positive group than in the HLA-B27-negative group; however, the difference was not significant (39.1% and 28.9%, respectively).Conclusion: Compared with northern Europe, HLA-B27-positive rate of patients with AS has been shown to be lower in Turkey. Except for the presence of syndesmophytes, there was not a statistically significant relationship between HLA-B27 positivity and clinical and radiologic findings