Summary: Zinc ion is crucial in synthesis, accumulation and secretion of insulin. It was showed that concentration of zinc in subjects with diabetes and prediabetes is lower than in healthy subjects. The correlation between lower zinc level and elevated fasting glucose, 2-h postprandial glucose and HbA1c was observed. It is assumed that zinc supplementation improves glycemic control – trials revealed reduced glycemic indicators. Moreover, zinc intake had beneficial effect on lipid profile (total cholesterol, LDL-cholesterol, triglycerides) and reduction of inflammatory biomarkers (hs-CRP, IL-6, TNF-a). Further studies are required to confirm the role of zinc supplementation in the adjunct therapy of diabetes and prediabetes.