From `86 to `96, 163 unrelated bone marrow donor (UBMD) searches for 158 children were performed in our institution. the 79 male and 79 female (pts) aged from 1 month (m) to 18 years (y) (mean: 7.2 y) at time of registration suffered from Severe Haematological Malignancies (n=108) including 69 ALL, 15 AML, 5 CML, 18 Myelodysplastic Syndroms, 1 Lymphoma; Non Malignant Hemopathies(n=23): 17 Aplastic Anaemia, 6 Fanconi; Metabolic Diseases/ID (n=27): 13 Hurler, 1 Gaucher, 2 Mucolipidosis, 1 Osteopetrosis, 6 FLH, 2 ID, 1 WA, 1 Kossman. They were eligible for a transplant procedure but the lack of family-member donor attempted us to search UBMD on international registries. The mean duration of searches was 16 m (range 9 days to 85 m). In `93, we speed the procedure to short the donor location delay reduced from 7 to 2 m(median). Eleven searches remain active today. For other pts, causes of cancellation are classified as follows: Complete Remission (CR): n=25 (17%), Deceased: n=23 (15%), Clinical status/disease progression: n=17 (11%), Allograft unrelated: n+35 (24%), Non identical Allograft Familiar: n=12 (8%), Cord blood transplantation: n=4 (3%), Autograft: n=10 (7%), Therapeutic failure/relapse (n=3), Other Causes (transfer, parents request, SAL/GCSF): n=17 (11%. All pts canceled because of disease progression died except 2 (1/2 autografted). When searches were stopped because of prolonged CR, evolution was favourable in 22/25 cases: 1 pt alive after autograft, 1 after transplant with geno id sib. born in the meantime, 1 pt died of relapse after prolonged CR of 7 y. Sixty-two patients were transplanted (39%): 35 from UBMD (3 pts transplanted twice with same UBMD), 12 from non id. familiar donor, 2 from geno-id. sibling (born in the meantime), 4 from familiar cord blood, 10 were autografted. The overall survival for unrelated BMT concerns 20/35 pts (57%): 7 ALL, 1 AML, 2 RAEBt, 1 JCML, 1 CML, 1 AA, 4 Hurler, 1 mucolip., 2 FLH. The event free survival for the 17 pts in CR with functional graft is of 59%. Among the 12 pts transplanted from non id. familiar donor, 2 are alive (1 ID/PNP, 1 FLH) but with graft failure. One patient (Hurler) transplanted with cord blood cells (HLA ½ id.) is alive but without engraftment. Four of 10 pts are alive in CR (40%). The 2 pts transplanted with geno-id brother are alive in CR. Among the 158 pts registered, 80 died (50%), 66 are alive with or without being transplanted (42%) of whom the 11 activated searches (2 BMT in progress) and 12 are lost of sight. For 3 pts who died, 1 IBMD was located too late for BMT. For 7 pts in prolonged CR, 1 or more UBMD are identified. For all high risk pts, BMT is the only therapeutic alternative and UBMD search is capital in their management.