These experiments were done to develop techniques to expose and manipulate the spinal cord in fetal rats, techniques that could be used to study spinal cord regeneration and transplantation. Adequate maternal anesthesia required a mixture of acepromazine-ketamine supplemented by thiopental. Fetal rats were operated on at 16 to 22 days of gestation. Fetal mortality increased as the age of the fetus decreased. Microsurgical techniques were developed to expose, divide, and transplant the distal spinal cord.