Histologically light microscopic structure, and immunohistochemically the presence and distribution of calbindin-D28k was investigated in the trigeminal ganglion of porcupine (Hystrix cristata). Many calbindin-immunoreactive neurons were distributed throughout the ganglia. All immunopositive cells were medium to large in size. Small ganglion neurons were not stained. There were three types of neurons as small, medium and large. Most of the neurons were enveloped by small satellite cells. The shapes of satellite cells were polimorphal and polygonal.