Phenol (I) is nitrated regioselectively by fuming nitric acid inside the cages of faujasite zeolites. While nitration as hexane slurry in CsY and molecular sieve 5 Å leads to predominant formation of para-nitrophenol (III), a remarkable ortho-selectivity is observed in solid state nitration to yield exclusively ortho-nitrophenol (II). Loading level of the substrate inside the supercage alters significantly the relative yield of the various products. Other advantage of this zeolite-mediated nitration include significant reduction in polynitration and absence of mixed nitrating agents.