Abstract： AIM To examine the distribution of gamma-aminob utyric acid B receptor (GABABR) in the central endogenous pain control system of the rat. METHODS　Immunohistochemical staining technique was used with specific antibody agains t GABABR. [ WTHZ〗RESULTS　Densely stained GABABR-like immunoreactive neuronal ce ll bodies were observed in the dorsal raphe nucleus (DR), median raphe nucleus (MnR), pontine raphe nucleus (PnR), nuc leus raphe magnus (NRM), nucleus raphe obscurus (ROb) and nucleus raphe pallidus (RPa). Add itionally, GABABR-like immunoreactive neuronal cell bodies were also found in the midbra in periaqueductal gray (PAG) and gigantocellular reticular nucleus pars α (GiA). G ABABR-like immunoreactive fibers and terminals were encountered in those nuclei as well. [ WTHZ〗CONCLUSION　Present results indicate that GABABR-like immunorea ctive neuronal cell bodies, fibers and terminals are located in the central endogenous pain control system. They might be involved in the regulatory effects upon this system.