Paired immunoglobulin-like receptor B (PirB) is a functional receptor of myelin-associated in-hibitors for axonal regeneration and synaptic plasticity in the central nervous system, and thus suppresses nerve regeneration. The regulatory effect of PirB on injured nerves has received a lot of attention. To better understand nerve regeneration inability after spinal cord injury, this study aimed to investigate the distribution of PirB (via immunolfuorescence) in the central nervous system and peripheral nervous system 10 days after injury. Immunoreactivity for PirB increased in the dorsal root ganglia, sciatic nerves, and spinal cord segments. In the dorsal root ganglia and sciatic nerves, PirB was mainly distributed along neuronal and axonal membranes. PirB was found to exhibit a diffuse, intricate distribution in the dorsal and ventral regions. Immunore-activity for PirB was enhanced in some cortical neurons located in the bilateral precentral gyri. Overall, the ifndings suggest a patt of PirB immunoreactivity in the nervous system after uni-lateral spinal transection injury, and also indicate that PirB may suppress repair after injury.