The sorption of radiocesium (137Cs) in sediments sampled from Lake Pamvotis of loannina was studied in a laboratory simulation. In a series of experiments, the kinetics of 137Cs sorption and 137Cs distribution profiles in sediment cores were investigated. The results have shown that a significant percentage of 137Cs (35%) is adsorbed in the sediments during the first 3 d, at a rate of 0.41 @ 0.05 d−1. The rest of 137Cs is adsorbed with the slower rate of 0.024 @ 0.004 d−1. 137Cs rapidly reaches (<5 d) a depth that does not exceed 3.5 cm. The sorption of 137Cs was found to follow Freundlich's empirical law, which describes the adsorption of most substances in solution to solids.