Find out the relationship between body mass index (BMI) and W.C with disease activity scorein AS patients and its association with clinical characteristics of AS. One hundred and five patients (75 male and 30 female) who visited rheumatology and medical rehabilitation centerin Sulaimani city were recorded in this cross-sectional study. Disease activity was measured by ASDAS-ESR in the hand-held calculator.BMI was calculated and waist circumference(W.C.) was measured and both were evaluated with disease activity score and disease characteristics in those with normal BMI and W.C and those with abnormal BMI and W.C.Data of one hundred and five patients were involved in this study with a mean age of 37±9.5 years with the predominance of male gender (71.4%). The mean BMI of the patients was27.2±4.6 kg/m², 28.6% of them were obese and 35.2% of them were overweight. Patients who were overweight, obese and increased W.C had significantly higher disease activity scoresand older compared to those who had normal BMI and W.C(p value<0.05).There was no statistically significant difference between the two groups in terms of peripheral arthritis,disease duration, clinical characteristics of AS, and gender (P value>0.05). Overweight, obesity and increased W.C are common among AS patients and significantly related to disease activity score and age, but not with disease characteristics and gender