Objective: This study aimed to establish reference intervals for lymphocyte subsets including CD4(+)CD25(high)FoxP3(+) regulatory T-cells (Tregs) in umbilical cord blood. Methods: Umbilical cord blood was obtained after birth from 120 healthy full-term neonates, who were born between November 2010 and November 2011. Lymphocyte subsets including Tregs were analysed using flow cytometer (Beckman Coulter, Fullerton, CA, USA), and the reference intervals were defined using non-parametrical percentile methods according to the Clinical and Laboratory Standard Institute guideline (C28-A3). Results: The reference intervals for lymphocyte subsets were: helper T-cells (CD3(+)/CD4(+)), 15.40-70.06%; cytotoxic T-cells (CD3(+)/CD8(+)), 9.65-34.28%; B-cells (CD19(+)), 4.50-29.59%; and natural killer cells (CD3(-)/CD16(+)/CD56(+)), 1.42-28.03%. The reference interval for Tregs was 0.35-9.07%. Conclusions: This study provides the reference intervals for lymphocyte subsets including Tregs in umbilical cord blood from healthy full-term neonates. These results could be used as fundamental data for clinical laboratory tests as well as future researches.