The review is aimed to explore the clinical and pathogenic spectrum of autoimmune diabetes including Type 1 diabetes and latent autoimmune diabetes in adults (LADA). Genetic susceptibility modifies age at onset in autoimmune diabetes. The most important genetic susceptibility to Type 1 diabetes and LADA is in the HLA region. Because of the age-related genetic factors, LADA can not be distinguished from classic Type 1 diabetes by genetics. Non-genetic factors contribute much to Type 1 diabetes, but little is known in LADA. Diabetes-associated immune process can occur in early childhood and can be predictive of an ongoing beta cell destruction. The management and prevention of LADA need to be investigated in order to define the best therapeutic strategy.