Two patients with beta-thalassemia and spinal cord compression due to extradural extramedullary hematopoietic tissue are presented and the related literature is reviewed. This rare complication, once diagnosed, may be treated readily with surgical decompression or radiation. The diagnosis is suggested by evidence of extramedullary hematopoiesis elsewhere and the presence of an extradural lesion, usually in the mid- and lower thoracic region, on myelography and, at times, a paravertebral mass on chest x-ray films. Our findings lend support to the hypothesis that such hematopoietic tissue in the spinal cord vicinity arises from embryonal rests in the extradural areolar tissue of mesodermal origin.