The relevance of the research is caused by the need to develop basic algorithms for processing and inversion of data from a new multi-coil multi-frequency multi-mode electromagnetic tool with toroidal coils designed for studying the electrical macroanisotropy of rocks, determining the saturation of reservoirs, identifying thinly bedded sandy-argillaceous oil-saturated intervals and fracture zones. The main aim of the research is to develop basic algorithms for processing and inversion of data from the new electromagnetic tool with toroidal coils for studying the macroanisotropic properties of reservoirs with complex geological structure (thinly bedded, fractured). Objects of the researches are the signals of the new electromagnetic tool with toroidal coils. Methods: finite-difference numerical simulation and comparative analysis of signals of the new electromagnetic tool with toroidal coils. Results. The authors have developed the basic algorithms for processing and inversion of data of the new electromagnetic tool with toroidal coils, among which: the algorithms of transforming the signals into the apparent resistivity and electrical anisotropy coefficient, selection of contrasting geoelectric boundaries, as well as software for numerical inversion with determination of the parameters of isotropic and anisotropic formations, taking into account the host medium. The computational algorithms are combined into a single computer program for quantitative interpretation of data from the new electromagnetic tool with toroidal coils. The algorithms are tested on noisy synthetic data. We have shown their efficiency when processing practical data from petroleum boreholes in the Volga-Ural oil and gas province. The investigations demonstrate that the new electromagnetic tool with toroidal coils has a high potential for use in geological sections of complex structure (thin-bedded, fractured).