EPR evidence for photoinduced electron transfer from beta-carotene and canthaxanthin to solvent molecules under 308-578 nm photolysis of frozen carotenoid solutions in CCl4, CHCl3, CH2Cl2, and CS2 has been obtained. The paramagnetic species are stable at 77 K and are attributed to carotenoid radical cations (Car(.+)) and solvent derived radicals, For a CS2 solution, solvent radicals are identified as CS2.- radical anions, and for chlorinated solvents, they can be assigned to either a predissociation species (R ... CI)(.-) or radical products R-.. The proposed reaction mechanism includes energy and electron transfer from the S-1 and S-2 excited singlet states of carotenoid molecules to the solvent to form an intermediate donor-acceptor complex (1)[Car ... Sol]* which decays yielding solvent-separated radical-ion pairs (Car(.+)... Sol ... Sol(.-)).