Objectives: The purpose of this study was to determine relationship between type 1 diabetes and vitamin D deficiency.
Background: Diabetes type 1 is a common disease in childhood. Prevalence of this disease is estimated about 35 million worldwide. Different studies indicated that vitamin D insufficiency and diabetes type 1 in children are related. This vitamin is essential for normal secretion of insulin. Studies showed the increasing destruction of insulin secreting b cells in the pancreas in animals with vitamin D insufficiency. Epidemiologic studies indicate that prevalence of diabetes 1 has a direct correlation with sun shining time. Another studies indicated that intake of 2000 unit of vitamin D in the first year of life, decreased diabetes type 1 risk. Childhood diabetes prevalence is three times higher in children with rickets. Avoiding vitamin D deficiency is essential for prevention of b cells destruction and it preservative effects on diabetes type 1 prevention in life cycle. Bener (2009) showed that there are differences between healthy child and diabetic child, regarding fractures, weakness and intestinal problems. Besides, it was showed that vitamin D deficiency's prevalence is higher in diabetic children compared with healthy children.
 Conclusion: instruction for vitamin D intake and exposure to sunshine can decrease the diabetes type1 incidence.