In this study, the rostro-caudal localization of the perikaryons of the intermedio-lateral nucleus (ILN), examination of the cytoarchitectonics and measurement of the short diameters of the cells are measured. For this purpose, serial transverse sections 6 cats and serial sagittal sections 2 cats of the spinal cord were stained with Kluver-Barrera; the Golgi-Cox method was also used (2 cats). Results were as follows : 1) The ILN neurons were found to extend from C_8 to L_4. 2) The cells in the ILN were grouped rostro-caudally (i.e. longitudinally) especially those in the T_2,T_3 and T_5-T_10 segments. 3) The cells in the ILN could be classified into three types : A) multipolar large cells : about 30μ. B) small round cells : about lOμ. C) spindle form cells : 10-30μ. 4) No difference in cell number between each half of the neurons could be observed. 5) The total neuron number ranged from 10,000 to 17,000 in each half. 6) The average number of neurons in one segment was about 700.