Objective : To investigate serum VEGF levels as an objective activity parameter and its relationship with clinical and laboratory parameters as well as MRI findings in ankylosing spondylitis (AS). Methodology : Twenty four patients with AS and 8 healthy matched individuals were recruited in this study consecutively. Cross-sectional study was planned and demographic, clinical, functional, MRI findings, and laboratory data of patients were evaluated. Disease activity, functional status, and quality of life were also assessed respectively, with Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), and Short-Form 36 (SF-36). Mander Enthesis Index (MEI) was used for evaluation of enthesis involvement. We examined serum concentrations of serum VEGF levels pg / ml in patients with AS and controls. Results : The mean value of serum VEGF levels in patients and controls were 316•4 pg / ml and 117•3 pg / ml, respectively. This difference was meaningful (p = 0.04). There was a significant correlation between VEGF level and C reactive protein level, albumin, C3, and IgA levels. MRI sacroiliitis grading showed significant correlation between VEGF levels and grades 1, 2, 3 and 4. A significant correlation between VEGF levels and distance of hand–floor, modified lumbar Schober’s test, distance of chin to chest and extra-articular manifestations was found. However, there was no significant correlation between VEGF levels with MEI, BASFI, BASDAI, and SF-36 (p ≥ 0.05). Conclusions : Serum VEGF levels were significantly higher in AS patients than controls. Serum VEGF levels may be a potential biomarker of axial inflammation and disease activity in AS