The aim of this study is to determine the radioactivity levels as a baseline for further studies and to obtain the distribution patterns of radioactivity in lake surface water around Izmir/Turkey. In this study, surface water samples were collected from three lakes around Izmir-Turkey. Surface water samples were analyzed for pH, mV conductivity and alkalinity content. The gross alpha/beta and uranium concentrations were investigated in the collected lake water samples. Mean gross alpha and gross beta activity concentrations in the surface water were found to be between (0.03 and 2.62) Bq l(-1) for Karagol Lake, (0.75 and 2.35) Bq l(-1) for Golcuk Lake, (0.03 and 1.77) Bq l(-1) for Cakalbogaz Lake, respectively. Uranium concentration varied between (0.05 and 900) mu g l(-1) for Karagol Lake, (0.05 and 0.95) mu g l(-1) for Golcuk Lake and (3.33 and 10) mu g l(-1) for Cakalbogaz Lake. Radioactivity contour maps were produced and their data were evaluated statistically. (C) 2009 Elsevier Ltd. All rights reserved.