The objective was to describe the necessary structure for treating diabetes patients in the primary healthcare system, as evaluated in Cycles I and II of the Brazilian National Program for the Improvement of Access and Quality (PMAQ) in 2012 and 2014, according to the municipalities' characteristics. A descriptive study was used to assess primary care units whose teams participated in Cycles I and II of the PMAQ in 2012 and 2014. The study used variables from Module I of the external evaluation of the PMAQ that addresses the primary care units' structure. Materials (150kg scale, sphygmomanometer, adult stethoscope, tape measure, blood glucose monitor, monofilament packs, ophthalmoscope, and capillary blood glucose strips); medicines (NPH and regular insulin, glyburide, and metformin); and physical space (clinical consultation room, pharmacy, reception/waiting room, and meeting room). All the medicines and the reception/waiting room increased by more than 10p.p. from 2012 to 2014. The prevalence rates for adequate structure of materials, medicines, and physical space in the primary care units were higher in 2014. Adequate structure increased as follows: for materials, from 3.9% to 7.8%, for medicines, from 31.3% to 49.9%, for physical space, from 15.3% to 23.3%. Municipalities with more than 300,000 inhabitants, higher Human Development Index (HDI), and lower coverage of the Family Health Strategy (FHS) showed higher prevalence rates for adequate primary care units. Units that adhered to Cycles I and II of the PMAQ showed improvement in their structures. However, there was a low prevalence of primary care units with adequate structures, besides differences in the services' structure according to population size, HDI, and FHS coverage.