Objective: Our objective was to study the association between obesity and vitamin D status and to compare vitamin D levels before and after supplementation according to weight status in hypertensive patients. Design and method: A retrospective cohort study, involving 1455 patients. Student's paired-samples t-test was used to compare vitamin D levels before and after supplementation. The Pearson Correlation “r” test was used to analyze the correlation between vitamin D, anthropometric indices (body mass index (BMI) and waist circumference (WC)) and systole blood pressure (SBP). Results: A negative correlation was noted between the anthropometric indices (BMI and WC) and the vit D level. A highly significant variation was reported between the level of 25(OH) D before and after supplementation (p<0.001), however, the response to vitamin D supplementation in obese patients was significantly lower than in normal weight subjects. The univariate analysis showed a significant association between obesity and male gender (p = 0.02), SBP (p = 0.08), the cumulative number of cardiovascular risk factors > 5 (p = 0.07). The multivariate analysis showed a significant association between obesity and male gender (p = 0.02), SBP (p = 0.08), the cumulative number of cardiovascular risk factors > 5 (p = 0.07). presence of obesity (p=0.01) and SBP more 150 mmhg (p=0.03) were predictor factors of poor response to vit D supplementation. Conclusions: Vitamin D deficiency is very common in obese subjects, specific recommendations for supplementation should be adopted according to body weight, diabetes and hypertension.