Introduction: Diabetes mellitus type 2 (DM2) is a public health problem considering its magnitude and repercussions.Objective: To determine the correlation between glycemic control and the level of knowledge about their disease in patients with DM2.Materials and methods: The sample consisted of 65 adults with DM2, aged between 55 and 74 years. The Michigan Diabetes Research and Training Center’s Revised Diabetes Knowledge Test was applied to measure the level of knowledge about DM2. Glycemic control was determined based on the last glycosylated hemoglobin value. Information on educational attainment, years of diagnosis of the disease and use of insulin therapy was obtained from clinical records.Results: Patients with a sufficient level of knowledge of their disease had better glycemic control than those whose knowledge was insufficient (p<0.001). There were no differences when comparing educational attainment (p=0.201), years of diagnosis of the disease (p=0.126) and insulin use (p=0.108) with glycemic control.Conclusion: Glycemic control in DM2 patients can be improved by delivering tools that allow them to be empowered with knowledge about their disease, regardless of their educational attainment, the duration of the disease course or the type of treatment.