Abstract: This multicenter retrospective study included 184 children with malignant and non‐malignant diseases who underwent UCBT between January 1998 and August 2012. The malignant disease group included 101 children with ALL, AML, CML, JMML, and MDS, and the non‐malignant disease group included 83 children with PID, β‐thalassemia, IMD BMF, and HLH. The median duration to neutrophil and platelet engraftment was 16 and 35 days in the malignant disease group vs 15 and 38 days in the non‐malignant disease group. The cumulative incidence of grade II‐IV aGVHD and cGVHD was 25.6% and 13.5% in the malignant disease group vs 19.7% and 11.1% in the non‐malignant disease group, respectively. The median duration and cumulative incidence of neutrophil and platelet engraftment, and the cumulative incidence of grade II‐IV aGVHD and cGVHD were similar between the two groups. Of the 184 pediatric patients, 114 patients survived during a median follow‐up period of 14 months (range 4‐138). The 5‐year OS and DFS were not statistically different between the two groups (56.3% and 46.1% in malignant disease group vs 68.5% and 52.8% in non‐malignant disease group). The above results indicate that UCB is a viable source for HSCT for children with malignant or non‐malignant diseases, especially in urgent cases. [ABSTRACT FROM AUTHOR]