BACKGROUND It is still unclear the ideal vitamin D dosage once the deficiency and insufficiency is treated. Once deficiency was corrected we prospectively treated patients with 2,000 IU of vitamin D3 to check whether this dosage is enough to keep them above the 30 ng/mL of 25-hydroxy-vitamin D (25[OH]D). METHODS One hundred and thirty-five Saudi Arabian men and women treatment naïve for the vitamin D deficiency and insufficiency were part of this study. History and clinical examination were done to rule out any metabolic bone disease. Weight and height was taken to calculate the body mass index (BMI). Patients who were vitamin D deficient (≥30 ng/mL), a standard treatment of 50,000 IU of vitamin D3 weekly for 3 months, a blood test for the vitamin D levels at the end of 3 months, maintenance dose of 2,000 IU of vitamin D3 for 3 months and a third blood sample after 3 months. RESULTS The data for 128 patients was available for analysis. The average age was 44.95±12.97 years with the mean BMI of 29.60±2.59 kg/m2. The baseline 25(OH)D level was 13.16±3.30 ng/mL. The increase in the level of 25(OH)D on 50,000 IU weekly was significant from 13.16±3.3 ng/mL to 36.97±4.67 ng/mL (P<0.001) and then 2,000 IU daily for next 3 months, the level of 25(OH)D dropped top 20.38±5.42 ng/mL (P<0.001). CONCLUSIONS Our study indicates that the maintenance dose of 2,000 IU of vitamin D is not enough for patients to keep the 25(OH)D levels above 30 ng/mL.