Amyloidosis is a pathological condition which consists on the accumulation of fibrillar proteins. This disease is characterized by extracellular amyloid deposits with a clinical variability depending on the affected tissue. Histopathological evidence indicates that diabetes mellitus type 2 (DM2) induces dementia development, specifically Alzheimer's disease (AD). It has been demonstrated in animal subjects that there is a possibility that aberrant signaling of insulin is a key factor in the induction of the pathology of AD. Recently, there has been newly emerged evidence regarding the relationship between the pathogenesis of Parkinson's disease (PD) and insulin resistance. On another note, the importance of the amyloid deposits in the patients' pancreas with DM2 was evidenced by the discovery of islets of amyloid polypeptide. This has generated interest in the search of the etiopathogenic role of DM2 in the carbohydrates' metabolism. Finally, it is important to consider DM2 as a risk factor essential for the formation of deposits of amyloid-β in patients' brains with dementia.