Introduction: The aim of this study was the analysis of the organizational aspects, treatments and outcomes of the program of allogeneic hematopoietic stem cell transplantations (HCT) from unrelated donors for children from Ukraine in the Transplant Center in Bydgoszcz, Poland over the period 2015–2020. Material and methods: Patients from Ukraine were referred via email by parents or by the Tabletochki Charity Foundation based in Kyiv directly to transplant physicians or to the Medical Office of Jurasz University Hospital 1 in Bydgoszcz. Results: Overall, 28 allo-matched unrelated donor-HCTs in 22 patients were performed. Children were diagnosed for malignant (n = 19) or non-malignant (n = 3) diseases. Most of the children were in advanced stages of the disease. The cumulative probabilities of hematological engraftment measured by neutrophil and platelet recovery were 90.6% and 77.3%, respectively. The cumulative incidence of acute graft-versus-host disease ≥2° and extensive chronic graft-versus-host disease were 40.9% and 27.7%, respectively. Overall, 11/19 patients with malignant diseases and 1/3 with non-malignant diseases were alive at the end of a median follow-up of 1.5 (range 0.1–6.5) years. Overall survival (OS) for all patients was 0.51 ± 0.11. Patients with malignancies at transplant standard risk had OS = 0.83 ± 0.15, while those with transplant high-risk had OS = 0.34 ± 0.15 (p = 0.025). A total of 10/22 children died. The treatment-related mortality rate was 6/22 (27.3%). The overall relapse rate among children with malignancies was 4/19 (21%). Conclusions: The program of transborder transplants for children from Ukraine was an important factor in international co-operation contributing to the establishment of a program of transplants from unrelated donors for children in Ukraine. The outcome was positive for more than half of the children referred to the program.