This paper describes a modification of a balloon-compression technique to produce spinal cord injury in adult rats. A 2-French Fogarty catheter is inserted into the dorsal epidural space through a small hole made in T10 vertebral arch, advanced cranially to T8-9 spinal level, and inflated for 5 min. Spinal cord damage is graded by increasing the volume of saline used to inflate the balloon. Quantitative neurological and histopathological outcomes are presented with three different volumes (10, 15, and 20 microl of saline) to characterize the gradation of injury. Volume of 15 microl produced complete paraplegia followed by gradual recovery, finally reaching approximately the middle of the scale used to quantitate the locomotor performance. With these animals, after 4 weeks, the center of the lesion shows complete loss of grey matter and partial sparing of the white matter. We conclude that 15 microl volume produced submaximal injury that will be useful for studying the pathophysiology and effects of protective therapies with this compression-injury model.