There was made the mathematical modeling of river waters pollution dissemination, for example at dumping of oil from the railway bridge across Rioni River (Western Georgia). The information about the quantity of oil, which reached the river outlet, was taken as starting and boundary conditions for modelling of oil dissemination and transformation in the Black Sea waters. The study of the dissemination of oil pollution at possible disastrous oil spill from tankers in the open sea near Kulevi oil terminal was also conducted. For modelling the river pollution the analytical solution of no steady-state diffusion equation in three-dimensional case was used. The study of sea pollution was made on the base of statistic simulation method (Monte Carlo method) - the computer tracing of transfer and transformation of oil portions-comparatively coarse particles intwodimensional case, the calculation of probabilistic characteristics of these processes. The data were provided about the spatiotemporal evolution of river and sea waters oil pollution. The features and the differences of ecological consequences of oil dumping in winter and summer conditions were marked. The results of the studies were included in the projects on assessment of environment influence of Tengiz oil railway transit over the territory of Georgia and functioning of Kulevi sea oil terminal.