DNA polymerase kappa (pol kappa) is a member of the Y-family of DNA polymerases that are thought to function in translesion synthesis (TLS) past different types of DNA damage. Here, we show that pol kappa-deficient mouse cells have substantially reduced (but not absent) levels of nucleotide excision repair (NER) of UV damage, as measured by several methods. Our results provide evidence for an unexpected role for pol kappa in mammalian NER.