Background Vitamin D is a vital lipid-soluble vitamin in the body, helping the growth and development of bones. Vitamin D deficiency in children has several adverse effects. The most important preventative factor is determining the deficiency at an early stage and prescribing vitamin D-containing supplements. Objectives To investigate the vitamin D status of children younger and older than 2 years and determine the utility of prescribing vitamin D supplements. Patients and Methods Three hundred healthy children who attended the pediatric clinic for routine assessments were enrolled in this study. Their parents were asked to complete a questionnaire, which included questions about demographics, nutrition, and supplements. Blood levels of vitamin D, calcium, and phosphorus were then measured. Results The final study consisted of 286 children, 140 males and 146 females, with a mean age of 4.46 ± 2.82 yr. Of these, 218 (76.22%) children, with a mean age of 5.09 ± 2.82 yr, had vitamin D deficiency, and 76 children (23.78%), with a mean age of 2.58 ± 1.88 yr, had normal vitamin D levels (P = 0.001). The mean level of vitamin D was 29.71 ± 14.42 ng/mL in 88 (30.8%) patients up to 2 years and 17.11 ± 14.02 ng/mL in 198 (69.2%) patients older than 2 years (P = 0.0001). Conclusions The vitamin D levels of children aged more than 2 years are lower than those of children aged less than 2 years. Thus, prescribing vitamin D-containing supplements in children older than 2 years may be beneficial.