We report on the first observation of electron paramagnetic resonance of iron and photo-EPR of nickel impurities in 6H-SiC crystals. Iron exists in Fe(3+) (3d(5)) charge state with electron spin, S = 3/2. Nickel exists in Ni(3+) (3d(7)) charge state with electron spin S = 3/2. Both impurities seem to occupy silicon sites in the 6H-SiC lattice. Possibility of using iron doping to obtain semi-insulating SiC crystals is discussed.