Anaesthesiologists frequently encounter patients with diseases of the endocrine system, in particular diabetes mellitus. The major risk factors for people with diabetes undergoing surgery are the associated end-organ diseases: cardiovascular autonomic neuropathy, joint collagen tissue, and immune deficiency. Due to the fact that endocrine diseases can be associated with significant peri-operative morbidity and mortality, it is critical that anaesthesiologists understand these disorders and when indicated request the appropriate investigations.