Geographical distributions and chemical speciation patterns of Cu, Zn, Cd, and Pb in sediment samples from Prut, a border river between Moldova, Romania and Ukraine, were investigated. Sediments were collected at 9 sites along the river in 2001 and 2002. Two separation schemes were used: the well-known sequential extraction procedure of Tessier et al. (1979), and a scheme focusing on the part of the metals associated with fulvic and humic compounds in the sediment (Donisa et al., 2003). From the sequential extractions it appeared that Cd was more mobile than the other metals occurring to 60-85% in the two first fractions (exchangeable + carbonate-bound). In contrast Zn was most closely associated (50-70%) with the residual fraction. Also Cu appeared mainly (50-80%) in the residual fraction, whereas Pb was most abundant in the oxidisable fraction (50-60%) followed by the residual fraction (ca. 30%). The extraction aiming at humus-bound metal fractions (humic + fulvic) showed that Cu was bound to about 30%, Cd was variable with a mean around 20%, whereas Zn and Pb were humus-bound only to 5-10% and <5% respectively. The percent of the humus-bound fraction bound to humic acid was of the order of 50-60% for Zn and Cd, 30-50% for Pb, and 20% for Cu. The humus-bound fraction of Pb was only around 10% of that recovered in the Tessier et al. oxidisable step, indicating that most of the latter was bound to sulphide rather than to organic matter. The total concentrations (mg/kg) were within the following ranges: Cu, 10-20; Zn, 30-100; Cd, 0.10-0.30; Pb, 5-12, indicating that the Prut river sediment is not heavily polluted in general with these metals. The highest levels were generally found within the lower stretches of the river.