Background: Relapsed stage IV neuroblastoma patients have rare chance for a long-term survival. Although benefits of allogeneic stem cell transplantation (SCT) from HLA matched sibling for relapsed neuroblastoma has been denied, SCT from HLA mismatched donor is still explored. We evaluated effects of HLA mismatched SCT as a salvage therapy in patients with relapsed neuroblastoma, especially in terms of Killer immunoglobulin like receptor (KIR) ligand compatibility. Methods: Seven patients with relapsed stage IV neuroblastoma received allogenic SCT from HLA mismatched donor in our hospital from 2007 to 2014. The median age was 6 (range: 2-9) years old at relapse, consisting of 4 boys and 3 girls. Three patients received allogenic SCT from KIR compatible donor (KIR match group). Two were from HLA haploidentical related family and one from cord blood. Other four patients received KIR ligand incompatible cord blood transplantation (KIR mismatch group). Results: All patients except for one could achieve the second complete response prior to SCT due to several different salvage chemotherapies. All three patients in KIR match group developed disease progression after SCT resulting in death. The time interval between transplantation and death were 4, 7 and 20 months, respectively. On the other hand, three out of four patients in KIR mismatch group were alive without any chemotherapies after transplantation for 13, 26 and 63 months, respectively. One patient in KIR mismatch group developed a local recurrence in his right femur bone, 9 months after CBT, but he received artificial bone displacement and alive without any further treatment. Finally, both progression-free and overall survival were significantly better in KIR mismatch group than in KIR match group (p=0.01, 0.04, respectively). Conclusions: CBT from KIR ligand incompatible donor could be an efficient salvage therapy for relapsed stage IV neuroblastoma if a patient achieves the 2nd remission prior to CBT.