To investigate the expression of nerve cell-specific transgene products in neural transplants, we implanted into the hippocampus of immunosuppressed adult Sprague – Dawley rats cell suspensions obtained from the septal region of the fetal brain of mice that carry the human neurofilament-light (hNF-L) gene. In grafts examined between 3 weeks and 7 months after transplantation, axons and nerve cell somata immunoreacted to antibodies specific to the human NF-L subunit. Thus, the hNF-L protein appears to be a suitable marker of these grafted neurons. Transgenic mice bearing the hNF-L gene may be a convenient source of donor tissue or be used as hosts for neural transplantation studies. Furthermore, the hNF-L promoter/enhancer elements in this transgene may help direct neuronal expression of heterologous genes that could influence nerve cell responses in either the transplant or host tissues.