Leukocyte adhesion deficiency (LAD) is a rare disorder characterized by the congenital absence of CD18 resulting in the loss of expression of leukocyte CD11/CD18 integrins on myeloid cells with resultant life threatening infections. Hematopoietic stem cell transplantation currently provides the only available cure for this disorder. Although there have been reports of some success in transplantation using related family member donors or unrelated marrow donors with either myeloablative or non-myeloablative prepartative regimens, there is little experience with the use of umbilical cord SCT. We present here the first report of a patient transplanted with unrelated donor cord blood (UCB) for severe LAD type 1. The patient was diagnosed at 2 months of age when he presented with failure to thrive, fever, mastoiditis, and lethargy. Laboratory evaluation revealed a WBC of 165,000 (predominantly neutrophils) and flow cytometry documented the absence of neutrophil expression of CD11b and CD18. He was treated with antibiotics and surgical drainage of his mastoid bone. Since no family donors were identified, and given the need to proceed with transplant expeditiously and to minimize the risk of GVHD, unrelated donor cord blood transplant was pursued using a non-myeloablative preparative regimen. A large (16.5 × 107 TNC/kg and 9.5 × 105 CD34 cell/kg) 10 of 10 antigen matched unrelated donor cord blood unit was identified. The preparative regimen included Campath-1H3 (10 mg/d iv days -21 to – 19), fludarabine (30 mg/m2/d iv days -8 to -4) and melphalan (140 mg/m2 iv day -3). GVHD prophylaxis consisted of CSA + mycophenolate. He engrafted and was transfusion independent by day 16. He had no evidence of GVHD, and donor-host studies revealed 40% donor on day 15. His donor chimerism fell to 16% by STR on day 41 confirmed 100% recipient by VNTR. His cyclosporine was discontinued and an extensive viral screen showed no evidence of CMV, EBV, HHV6, adenovirus, or Hepatitis B. Over the next several months, his donor chimerism slowly rose to 48% where it has remained stable for the past 7 months with 44% of his granulocytes positive for CD11b/CD18. He remains clinically well off all immune suppression 13 months post-transplant with normal growth and development. Conclusion: UCB is a viable source of stem cells for LAD patients.