Enzyme deficiency was corrected in mice after allogeneic bone marrow transplantation with occurrence of graft versus host disease. beta-Glucuronidase-deficient C3H/HeJ mice were treated with total lymphoid irradiation. Normal bone marrow cells (30 X 10(6)) from BALB/c to C3H/HeJ chimeras (>90 percent circulating donor-type cells) without graft versus host disease. beta-Glucuronidase activity increases to normal levels in all chimeras as measured in the liver and in the plasma. Activity was maintained throughout an observation period of 7 months.