This survey presents both the importance of diagnosing dementia in its early stages and the importance of initiating treatment, also in the early stages, in patients with Type 2 Diabetes Mellitus. The impact of this complication on the diabetic patient, on those around him, as well as the socioeconomic implications, transform this disease from one of less significance in its early stages to one requiring increasing monitoring and care as its severity increases. In the group studied the incidence of dementia in patients with type 2 diabetes was identified according to the level of severity of dementia: mild, moderate or severe. It is expected that more and more elderly patients with type 2 diabetes will develop dementia over shorter timescales. This complication can be avoided or slowed down by early diagnosis of type 2 diabetes and prompt initiation of treatment.