Type 1 diabetes (T1D) is a chronic disease that typically manifests itself in childhood through the autoimmune destruction of pancreatic beta cells, resulting in a lack of production of insulin. T1D is a multifactorial disease with a strong genetic component that is thought to interact with specific environmental triggers. Several genetic determinants of T1D were already established before the era of genome-wide association studies, primarily with the HLA class II genes, encoding highly polymorphic antigen-presenting proteins that account for almost 50% of the genetic risk for T1D. The recent development of high-throughput single nucleotide polymorphism genotyping array technologies has enabled investigators to perform high-density genome-wide association studies in search of the remaining T1D loci. Combined with the well-established genes known for many years, 16 loci have now been uncovered to date as being robustly associated with the pathogenesis of this phenotype.