Disclosed herein are methods and compositions for inactivating MEW genes, using zinc finger nucleases (ZFNs) comprising a zinc finger protein and a cleavage domain or cleavage half-domain in conditions able to preserve cell viability. Polynucleotides encoding ZFNs, vectors comprising polynucleotides encoding ZFNs and cells comprising polynucleotides encoding ZFNs and/or cells comprising ZFNs are also provided.