The advance of health conditions is propitiating the progressive increase of longevity and life expectancy. Studies have identified the existence of a connection between Diabetes Mellitus and (DM) and dementia. The hyperglycemia can be a significant factor for the incidence of Alzheimer, which could be a secondary cause for dementia. Type 2 Diabetes Mellitus (DM2) is associated to cognitive and functional deficits and, one of the tools, which can be used to assess executive functions, is the WCST. The objetive was the assessment of the cognitive prejudice in older people with DM2 through the WCST. Two hundred and fifty four (254) old people of both genders, with 60 years of age or older, divided into 44 persons with a DM2 diagnosis and 210 old people of the control group from the general population. The design was that of a quantitative and transversal study. The instruments used were: sociodemographic filing cards, WCST, MMSE, BDI, BAI, GDS. The Vocabulary, Coding, Digit Span, Block Design and WAIS – III sub-tests. The results showed there were a significant difference in the performance of old people with DM2, when compared to old people of the control group in four describers of the WCST, cognitive prejudice. The old people with DM2 showed intensity of depressive and anxiety symptoms of statistically larger regarding the group control.