In recent years, there has been increasing interest in the significance of natural radionuclides, particularly Po-210, in the marine environment. Po-210, a naturally occurring alpha emitter, accumulates in marine organisms and reflects differences in their diets. In the literature, there is no data for Po-210 and Pb-210 activity concentrations for fish species on the Turkish coast of Aegean Sea. Therefore, in this study, multiple fish species were collected from six stations seasonally on the Turkish coast of Aegean Sea and were analyzed for their Po-210 and Pb-210 content. The Po-210 and Pb-210 concentrations in the fish samples were found to vary from undetectable levels to 499 +/- 44 Bq kg(-1) dry weight (dw) and from 1.0 +/- 0.3 Bq kg(-1) to 35 +/- 4.0 Bq kg(-1) (dw), respectively. There were no significant differences in the activity concentrations of Po-210 and Pb-210 in fish samples between seasons (ANOVA, P > 0.05). The highest dose contribution of Po-210 to humans was calculated to be 10,530 mu Sv year(-1). (C) 2012 Elsevier Ltd. All rights reserved.