Background: The aim of this study was to examine the effect of dietary education on glycemic control in patients with any type of diabetes at four-week and two-year follow-ups. Methods: A two-year prospective study was conducted in three phases: before, four weeks after, and two years after an educational program. The participants were patients diagnosed with diabetes who were receiving insulin or oral hypoglycemics and who attended the Diabetes Clinic of the General County Hospital Na&scaron / ice, Croatia to receive their treatment. The questionnaire and educational program were created for the purpose of this study. Measurements were made (fasting blood glucose, glycated hemoglobin, body mass index, blood pressure, knowledge test) at baseline, four weeks and two years after education. Results: A total of 109 participants took part in the study, of which 56 (51.4%) were on insulin therapy and 53 (48.6%) were on oral therapy, after two years, 78 (72%) subjects were followed up with. There was no control group. At the two-year follow-up, participants with insulin therapy had significantly higher glycated hemoglobin (Mann&ndash / Whitney U test, p = 0.035). Significant differences were observed in fasted blood glucose (Friedman&rsquo / s test, p = 0.001), diastolic pressure (Friedman&rsquo / s test, P = 0.018), and glycated hemoglobin (Wilcoxon test, p < / 0.001) between Phase 1 and Phase 3. Conclusions: Education has a positive effect on adherence to recommended diet and glycemia regulation in diabetes patients after four-week follow-ups. However, after two years, participants showed a decrease in adherence to recommended diet and increased glycemia.