Results of radiomagnetotelluric (RMT) soundings with use of various modifications of this method (foot, mobile and controlled source ones) on landfills of industrial wastes on the Karelian Isthmus are considered. A landfill in the settlement Morozova near St. Petersburg was formed as a result of a long-term warehousing of toxic wastes by the sulfuric acid manufacture. In the adjacent to the landfill territory investigations by the foot and mobile modifications of the RMT method were conducted and a polluted zone was contoured. Another landfill of debris in a former sandy career is located in the Vyborg area. A survey by the controlled source modification of the RMT method was fulfilled. As a result the contouring of the wastes was realized and the structure of the landfill was studied.