Man has always been surrounded by metals. However, entry and distribution of metals throughout history has remained unchanged. In this paper samples of osteological remains from the period of the 9th century, discovered at the site Ostrovica (Bribir County) and Naklice (Klis County) were analyzed on metal content. The content of all toxic metals (Pb, Cd and Hg) as well as of important archaeological metals (Ca, Sr, Zn, Cu, Fe and Mn) were determined. The metals were quantified using atomic absorption spectrometry (AAS). Accuracy and precision of the method were confirmed by analysis of the standard reference material. This work is a contribution to the existing knowledge of life style and diet of the early Croatian population who lived in the area of Klis and Birbir in the Middle Ages. The development of civilization and industrialization (21th century) contributed to increasing amounts of toxic metals in the biosphere in relation to the Middle Ages (9th century). It was found that exposure of the archaeological population to lead was lower (0,61 mg Pb/kg) than exposure of the "modern" man (4,42 mg Pb/kg). Different living conditions and different diet between the "modern" and the medieval population gave rise to a different distribution of metals. The increased ratio of Sr/Ca (1,23 x 10 -3 ) indicates that the diet wasmainly represented by food of plant origin, while the ratio of Zn/Ca was extremely small (0,19 x 10-3 ) due to small intake of foods of animal origin - meat. There was a statistically significant difference in the distribution of metals between men and women. Men ate more food of animal origin (high Zn), while women ate more food of plant origin (high Sr). There were no differences in the distribution of metals between men according to age, while differences were present between women. They were incurred as a result of metabolic processes (Sr is higher in the age group 26-39 years). In relation to the archaeological sites statistically significant differences in both adult and children were also found. A very low concentration of Zn (36,06 mg/kg) was found in archaeological bones belonging to children in the Naklice group, indicating a very low intake of foods of animal origin.