Abstract: Spinal evoked potentials (SEP) epidurally recorded from the ipsilateral dorsal columns of L_3-4 in anaesthetized rats following stimulating the common peroneal nerve consisted of a fast triphasic spike potential, wave A; slow negative waves, N₁ and N₂; and a positive wave, P. These waves remained stable throughout the period of blank control up to 2-4 hours. In the course of graded compression at L_4-5 and neighbouring segments caudal to them, no alteration was seen in the latency of wave A; the peak latencies of waves A and N were prolonged as graded compression increa sed progressively; the amplitude of waves A, N and P linearly decreased with increasing intensity of pressure and when the compression intensity came up to 225 (X) mmHg, waves N and P disappeared, while wave A remained and became a final potential. After removal of the compression, which had lasted 5 minutes at the leval of 300 mmHg, the a mplitude of SEP recovered quickly in the first 15 minutes and then the recovering rate slowed; recovery of slow waves was better than that of fast wave; the wave A’s peak latency recovered synchronously with retrieval of its amplitude, whereas the restoration of the peak latency of wave N was slower than that of its amplitude. These results indicate that the spinal cord is sensitive to mechanical compression and the decrease in function of the spinal cord correlates linearly with the increase in intensity of the pressure.