We mapped sympathetic renal preganglionic neurons in the rabbit spinal cord using Herpes simplex virus retrograde transneuronal tracing after application of the virus to the renal nerve. Virus-positive neurons were found in the spinal cord from T7 to L2, principally in the ipsilateral intermediolateral cell column. Renal and adrenal preganglionic neurons are largely separate populations. Extensive nonspecific spread of virus from infected cells to neighboring neurons does not appear to occur.