Reported associations between vitamin D receptor (VDR) polymorphism and type 1 diabetes mellitus vary across ethnic groups. We studied the association between type 1 diabetes and 4 VDR gene polymorphisms (Bb, Ff, Aa and Tt) in an Iranian population. A group of 69 patients with type 1 diabetes mellitus and 45 unrelated healthy subjects were recruited. The prevalence of VDR polymorphisms in 4 restriction fragment length polymorphism sites including BsmI, FokI, ApaI and TaqI were analysed in patients and controls. The frequencies of 3 genotypes (Aa, FF and Bb) were significantly higher in the patient group. The relationship between VDR gene polymorphisms and onset pattern of diabetes was not significant. There were no significant difference between the genotype frequencies and chronic complications of diabetes, but the relationship between the Ff genotype and ketoacidosis was significant. Our results differ from previous polymorphism studies in other regions.