We present a case of acute spinal epidural hematoma[EDH] following unilateral laminectomy for bilateral decompression[ULBD]. A 45-year-old male presented with severe multi-level spinal stenosis underwent ULBD on the left side at the L2-3 and L3-4 level. Five hours after operation, paraparesis developed along with severe bilateral buttock pain. The CT scan showed an acute spinal EDH at the L2-3 level. The acute spinal EDH was successfully decompressed after emergency decompressive surgery with performing an additional laminectomy on the contralateral side at the L2-3 level. Although ULBD is an effective minimally invasive surgical technique for treating spinal stenosis, the possibility of acute spinal EDH should be kept in mind, as happened in our case.