The thalassemias are hereditary quantitative disorders of globin synthesis. Depending on the type of globin chains in deficiency we distinguish alpha and beta thalassemias. The gene responsible for the synthesis of beta-globin chain is coded on the 11th chromosome. So far, over 200 beta-globin gene mutations responsible for different clinical presentations of beta thalassemia have been discovered. Beta thalassemia minor doesn’t usually include clinical signs of an illness but manifests in red blood cell count (lower MCV and MCH). So far we haven’t been well informed of the prevalence of beta thalassemia minor in Croatia. In this scientific paper we conducted the research of beta thalassemia minor among blood donor population from Central Dalmatia. The initial group of research subjects consisted of 3,000 blood donors from Šibenik-Knin and Split-Dalmatia counties who had a comprehensive blood test done with their blood samples. Every subject whose MCV was under 78 fL (145 subjects) had hemoglobin electrophoresis and every subject with HbA2 over 3.7% was diagnosed with beta thalassemia minor. There were 5 subjects (0.16% subjects) in total with this diagnosis. Three subjects (0.1%) had Hb Lepore variant. During the second part of research 14 subjects diagnosed with beta thalassemia, inhabiting the same area of Central Dalmatia, had beta-globin gene analysis. This research discovered 20 variations in beta-globin gene, of which 7 haven’t yet been described in literature. Mutations found in our subjects were compared to previously described mutations in neighbouring countries, the Mediterranean Basin and other countries in the world. Some of the mutations matched the mutations in neighbouring countries, but some were surprisingly identical to the mutations in remote areas (India, Bangladesh, Iran). All of the mutations discovered in this research had a mild clinical picture of beta thalassemia. In conclusion, this research led to the first insight into the genetic background of beta thalassemia among a part of Croatian population and could encourage further research of this illness in Croatia and other countries from this region.