This invention provides an device for electrical stimulation of the spinal cord. The device has an electrode assembly with a sufficiently thin profile to be implanted between the pial surface of the spinal cord and the dura mater, and secured to the dura. Electrodes on the electrode assembly are directed towards the surface of the spinal cord, and connected through the dura to a signal generator located outside the dura. Following implantation, the subject is treated by transmitting electrical signals from the signal generator through the leads to the electrodes, stimulating the subject's spinal cord.