The therapeutic value of delivering recombinant uricase to human patients has been appreciated for decades. The development of therapeutic uricases has been hampered by the fact that humans do not encode an endogenous uricase and therefore most recombinant forms of the protein are recognized as foreign by the immune system and are therefore highly immunogenic. In order to both shield and stabilize the active enzyme, we encapsulated a functional ancestral uricase in recombinant, noninfectious Qβ capsid nanoparticles and characterized its catalytic activity. Oral delivery of the nanoparticles moderated key symptoms of kidney dysfunction in uricase-knockout mice by lowering uric acid levels. Histological kidney samples of the treated mice suggest that delivery of recombinant uricase had a protective effect against the destructive effects of uric acid that lead to renal failure caused by hyperuricemia.