Air can be introduced into the epidural space during the loss of resistance technique used to identify needle entry into the epidural space. Complications resulting from the injection of air into the epidural space include pneumocephalus, spinal cord and nerve root compression, retroperitoneal air collection, subcutaneous emphysema, venous air embolism, and possibly, incomplete analgesia and anesthesia. We experienced a case of a large epidural collection of air following epidural anesthesia attempted one month before. The CT scan revealed epidural air extending from L1-S1 with moderate compression of nerve root at L4-5.