Exposure to infant milk formula (IMF) or cow's milk in the first year of life and its association with susceptibility genes has attracted much attention in their possible role in inducing autoimmune destruction of islet beta cells and Type 1 Diabetes (T1D). Aim: To investigate the relationship between exclusivity and duration of breastfeeding and the genetic basis of this disease in patients with TID. Methods: The study included 24 diabetic children with TID matched with 21 controls. All the children were exposed to detailed history of the disease process and anthropometry for weight, height and body mass index. Blood samples were collected from all 45 cases for measuring HLA-DRB1 allelic polymorphism for the susceptible genes of HLA-DRB1 0301, 0302, 0401 and 0402 by polymerase chain reaction sequence specific primer (PCR-SSP) done by genomic DNA extraction using Genomic DNA purification kits. Results: Allelic polymorphism for the susceptible genes of HLA-RB1 were shown to be higher in the diabetic group compared to the control group especially for the 0302 and 0401 alleles at P0.05. TID cases who were exposed to IMF early in life exhibited earlier onset of the disease, more frequent episodes of DKA and significantly higher BMI at P