Background: Lack of adherence to treatment may hamper the management of type 2 Diabetes Mellitus. Aim: To identify if there is a profile of psychological variables associated with adherence to treatment and complications in patients with type 2 diabetes mellitus. Material and methods: The psychometric instruments Multidimensional Scale of Locus of Control in Health, Locus of Control of Rotter and Inventory of Temporary Orientation of Zimbardo & Boyd were applied to 192 patients aged 64 ± 10 years (78% women) with type 2 diabetes attending public primary health clinics. Adherence to treatment was assessed using glycosylated hemoglobin levels. Results: There was an inverse association between glycosylated hemoglobin and adherence to treatment (pBackground: Lack of adherence to treatment may hamper the management of type 2 Diabetes Mellitus. Aim: To identify if there is a profile of psychological variables associated with adherence to treatment and complications in patients with type 2 diabetes mellitus. Material and methods: The psychometric instruments Multidimensional Scale of Locus of Control in Health, Locus of Control of Rotter and Inventory of Temporary Orientation of Zimbardo & Boyd were applied to 192 patients aged 64 ± 10 years (78% women) with type 2 diabetes attending public primary health clinics. Adherence to treatment was assessed using glycosylated hemoglobin levels. Results: There was an inverse association between glycosylated hemoglobin and adherence to treatment (p