Four patients with chronic refractory immune thrombocytopenic purpura (ITP) received human umbilical cord-derived mesenchymal stem cells (hUC-MSCs). The hUC-MSC dose was 5×107 to 1×108. Complete remission (CR) was achieved in three patients in 12 months and one patient in 24 months. Three patients received the second hUC-MSC transplantation with the same dose. The median time between hUC-MSC transplantation and response was 12.5 days (range, 7-16). There were no severe adverse events during and post hUC-MSC transplantation. During follow-up (median, 17 months; range, 13-24) no other immunosuppressive drugs were used post-first hUC-MSCs transplantation. In conclusion, hUC-MSC transplantation is a reasonable salvage treatment in chronic refractory ITP. Prospective randomized large-scale clinical trials are needed to further elucidate the efficacy of hUC-MSCs transplantation therapy on ITP.