Background: Psoriatic arthritis is a chronic, immune-mediated, inflammatory arthropathy that presents with inflammation of the joints and entheses, including those of the axial skeleton, and is associated with increased mortality from cardiovascular disease. The aim of the work is to evaluate serum level of sclerostin in patients with psoriatic arthritis and to correlats its level with the severity and activity of psoriatic arthritis. Methods: This case control study included (50) subjects classified into two groups: Group I:  30 patients with psoriatic arthritis. Group II: 20 healthy age and sex matched individuals as a control group. Results: there were no statistically significant differences between case group and control group, with a mean value of 42.45±12.90 vs 41.05±9.84 respectively. Regarding sclerostin , it found that there were no statistically significant differences between case group and control group with a mean value of 2787.92±1838.06 vs 2235.53±1830.67 respectively, And it found that there were highly statistically significant differences between groups with high mean value in patients with psoriasis group of 4276.72±1239.7 when it compared with other groups. Conclusion: The significantly higher serum sclerostin levels in PsA patients, compared with controls; there was positive significant correlation between sclerostin and each of age and PASI score. Sclerostin plays an important role in the pathogenesis of PsA and its associated bone damage, either systemic or localized.