This study investigates proliferation and apoptosis of olfactory ensheathing cells in cocultures with spinal cord tissue. Proliferation of ensheathing cells was significantly increased when cocultured with explants from uninjured spinal cord, and spinal cord that had been subjected to chronic contusion or chronic needle stab injury, but not to acute needle stab injury. Proliferation rate was highest in cocultures with chronically stabbed cord tissue. Contaminating (p75NGFR-negative) cells in the cultures showed a significantly higher proliferation rate than ensheathing cells. Apoptosis of ensheathing cells was significantly increased in cocultures with acutely stabbed spinal cord explants compared with chronically contused spinal cord explants. These results suggest that delaying transplantation after spinal cord injury may be beneficial to ensheathing cell survival.