The review summarizes the aspects of utilization of a high-resolution 2-mm waveband EPR spectroscopy combined with the modified methods of spin label and probe, steady-state saturation of spin-packets and saturation transfer in the study of conducting polymers. The theoretical background of the magnetic parameters, saturation, relaxation and dynamics study of nonlinear charge carriers in conducting polymers is briefly described in the first part. The second part deals with the peculiarities of EPR experiments at 2-mm waveband. The final part is devoted to an original data obtained in 2-mm waveband EPR study of the nature, relaxation and dynamics of paramagnetic centers delocalized on nonlinear charge carriers as well as the mechanisms of charge transfer in polyacetylene, polythiophene, poly(p-phenylene), polypyrrole, poly(bis-alkylthioacetylene), polyaniline, and poly(tetrathiafulvalene) with different doping levels