An evaluation of the radioecological sensitivity of the coastal marine regions can be used to improve risk management and decision-making systems, especially the development of response strategies, by defining the most sensitive areas. Environmental sensitivity analysis has been carried out for six marine coastal regions for a single deposition of 1000 Bq/m2 for radionuclides 137Cs, 90Sr, 131I and 239Pu. The analysis has been based on dose calculations during the 1st year, 2nd year and 10th year after releases of radionuclides for adults and children of 1 and 10 years of age. The calculations have been carried out by the compartment model, which includes the processes of dispersion of radioactivity in water - sediment environment and accumulation of radionuclides by marine organisms. Doses to man are calculated on the basis of seafood consumption. Results show that for all regions the radiation doses for adults are significantly higher than doses calculated for children. Further, the doses calculated for the first year dominate the doses of the second and tenth year following the releases of radionuclides. Calculations also indicate that doses vary greatly for different radionuclides; and the dose levels for the same radionuclide vary greatly in different marine environments.