Successful demonstrations of behavioural recovery in a variety of lesion and mutant animal models have encouraged the application of neural transplantation to the alleviation of neurodegenerative disease. Apart from the continuing shortage of foetal tissue, the major problems to be resolved for successful application of neural transplantation to humans are: first, immune rejection of allograft tissue and its pathological consequences to both graft and host tissue; and second, the establishment of normal and extensive graft-host connectivity. Recent developments in transplant research are beginning successfully to apply a number of strategies to resolve these problems.