This study investigated the relationship between arsenic concentrations in drinking water in four towns/villages in eastern Croatia and corresponding hair arsenic concentrations of residents. The mean arsenic concentrations in community drinking water samples were 0.14, 37.88, 171.60, and 611.89 mu g/l. The corresponding mean concentrations of the element in hair samples of subjects residing in each of the localities were 0.07 (n=11), 0.26 (n=17), 1.74 (n=11), and 4.31 mu g/g (n=23). Chronic exposures to arsenic levels estimated in three investigated locations could present a serious health threat to around 3% of Croatian population. (c) 2004 Elsevier B.V. All rights reserved.