The aim of this study was to evaluate functional disability and quality of life (QOL) in patients with ankylosing spondylitis (AS) and determine the relationship between functional status and measures of clinical condition including QOL. Fifty-one AS patients (45 male, six female) with a mean age of 37.2+/-10.8 years were included. The demographic data of the patients were recorded. Their clinical status was assessed using the Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Radiology Index (BASRI), and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Global pain of the patients was determined with a visual analog scale (VAS), and QOL status was evaluated with the Nottingham Health Profile (NHP). Twenty-seven patients (52.9%) had peripheral articular involvement. Sixty percent had mild-to-moderate and 25.4% of the patients had severe functional disability, while 5.8% did not report any functional loss. A significant change in the mean scores of all clinical measures except BASRI was observed between patients with and without peripheral arthritis. The clinical measures of disease (BASRI, BASMI, and BASDAI) were all correlated with each other and with laboratory variables. The strongest factors correlating with functional loss were BASMI and BASDAI. The scores of all sections of the NHP were significantly higher, indicating a poor quality of life in AS patients. Peripheral joint involvement had a significant role in the deterioration of QOL. Physical domains of NHP such as pain and physical activity had highest correlations with functional disability, whereas psychosocial domains of NHP were found to correlate more highly with BASDAI and VAS pain scores. These results show the effect of AS, especially when the disease is active and associated with peripheral involvement. In conclusion, current management strategies should focus on decreasing pain, maintaining physical activity, and efforts to improve psychosocial health aspects for increasing QOL in patients suffering from AS.