The effect of three different neurotrophins on axotomy-induced death of adult rat sensory neurons was examined. The ventral branch of the 13th spinal nerve was transected and the corresponding neurons in the 13th thoracic (T13) dorsal root ganglion (DRG) were pre-labelled with Fast Blue (FB). For a period of 4 weeks, animals received either no treatment, continuous intrathecal infusion of phosphate buffer, nerve growth factor (NGF), neurotrophin-3 (NT-3), or brain-derived neurotrophic factor (BDNF). Labelled neurons remaining after this period were counted. Inert, or no treatment, resulted in extensive loss of the DRG neurons. BDNF application was virtually non-effective, while NGF or NT-3 resulted in a greater number of FB-labelled neurons compared to normal controls. This suggests that NGF and NT-3 are survival factors for adult sensory neurons with a therapeutic potential in peripheral nerve injuries.