OBJECTIVES To estimate the multimorbity associated with diabetes mellitus type 2 and its relation to pharmaceutical cost in a primary health care setting. METHODS Cross-sectional study during 2012. A health region of 5,150,540 population  was analysed to determine the diabetic individuals. 350,015 diabetic individuals were identified through clinical codes using the ICD-9-MC classification and the 3M Clinical Risk Groups software. We analyzed the consumption of pharmaceutical and blood glucose reagent strips. All measurements were obtained at individual level. RESULTS The raw prevalence of diabetes was 6.7%. All patients were stratified into four morbitity groups. The first group corresponded to the initial state (CRG 1-4); the second group included the core multimorbidity patients in the intermediate and advanced stages (CRG 5-7); the third group included patients with diabetes and malignancies; the last group was of patients with catastrophic statuses, manly ERSD. The most common comorbitities in the patient group for CRG 5 to 7 were hypertension (47% - 97%), dislipemia (50.9% - 59%) and cardiovascular disease (18% - 39.9%). The average cost of insulin was € 117.1. The average cost of oral antidiabetic agents secretagogues was € 15.2 and was highest in the CRG 5 to 7 group at € 16.3. The average cost of non-secretagogue oral antidiabetic agents was € 212.9 and was highest in the CRG 5 to 7 group at € 232.8. The total average cost was € 476.5 in CRG 1-4 group, € 1350.5 in CRG 5-7 group, € 2174.1 in CRG 8 group  and € 2840.5 in CRG 9 group.  CONCLUSIONS Diabetes is characterised by a strong presence of other chronic conditions and events related to its development throughout life. This multimorbidity has a great impact on the pharmaceutical cost.