The article addresses determination of economic efficiency from the use of a two-layer foundation for transmission line portal towers in comparison with traditional design solutions. Three types of foundations for towers were considered as competing options: a monolithic reinforced-concrete foundation, a prefabricated foundation according to the serial design of the contractor and a two-layer foundation with a pyramidal base according to patent IPC E02D27/01. Construction is performed in an area with high seismic activity (8 points). Structural design of the foundations was carried out with account for the following loads: self-weight, wind in X-direction, wind in Y-direction, tension without account for atmospheric ice, tension with account for atmospheric ice, weight of a service man, turbulence of wind in X-direction, turbulence of wind in Y-direction, seismicity in X-direction, seismicity in Y-direction. A numerical experiment was carried out with the use of the ANSYS software package; the foundation structures and the soil mass were simulated. The design process revealed that there was no substantial difference in the settlement between three types of models, and that the settlement did not exceed the acceptable limit. During structural analysis with account for a special combination of forces in the principal reinforcement of the bottom grid, the optimal cross-section for each model was selected. Economy of principal reinforcement when using a two-layer foundation was 49% as compared to a monolithic foundation, and 30% as compared to the serial design.