The results of the study of radical pairs photoinduced in P3DDT+PCBM composition by the photoinduced EPR method are reported. Paramagnetic susceptibility of polarons and fullerene ion-radicals formed at the sample irradiation by laser is shown to depend on the quantum energy of the laser used. Spin-lattice and spin-spin relaxation times of both types of radicals were obtained by the steady-state saturation method in wide temperature region. Radical pairs collapse at ca. 160 - 180 K and the mechanism of this process is discussed.