Bone marrow transplantation (BMT) was primarily used for the treatment of hematologic malignancies and aplastic anemias. BMT has been successfully applied as curative treatment in a series of lethal congenital disorders but among more than 1000 inherited metabolic diseases only 20 of them can be corrected by transplantation. The inborn error must be expressed in the stem cells. The genetic disorders that can be cured include congenital immune deficiencies, osteopetrosis, and congenital lysosomal storage diseases, mucopolysaccharidosis and lipidosis. BMT with an HLA matched donor is successful in 60% of patients with severe combined immune deficiency and Wiskott Aldrich syndrome. Results are good in osteopetrosis if BMT is performed early. Encouraging results have been reported in Hurler disease and in Gaucher disease.