Mice were grafted with allogeneic compact and cancellous bone. The bone used was fresh and preserved by either lyophilization or deep freezing. Preserved grafts were radiosterilized by a dose of 3.3 MRads. The immunization of recipients was assessed by a modified migration inhibition test based on migration of cells from three-dimensional clot culture. Both preservation methods seem to change bone immunogenicity and enhancement of migration instead of inhibition occurring in the case of fresh bone was noted.