Background and Objective: Vitamin D (Vit.D) has an important role as immunoregulator. Its deficiency is suggested as a risk factor for respiratory system infection. In this study the serum Vit.D level in pneumonia and healthy children will be compared.

Methods: This study is a prospective case control study and contains 31 children between 6 and 60 months old hospitalized because of pneumonia and 40 healthy children between 6 and 60 months old. Serum Vit.D level in these two groups were measured and compared with P value less than 0.05.

Results: There was significant difference between “weight for age” but not in “height for age “Z-score. There was no significant difference between serum Vit.D level in the two groups. The mean serum Vit.D level in case group was 30.71 ng/ml and in control group was 31.89 ng/m.l (P=0.77)

Conclusion: We found no significant difference for frequency of Vit.D insufficiency between the two case and control groups. Maybe it is because of consuming supplemental Vit.D by most of infants and toddlers in Iran. More study with paying attention to this factor can be helpful.