Ex-vivo expansion of haematopoietic progenitor cells from umbilical cord blood is an interesting strategy to obtain a sufficient number of transplantable cells. Telomerase may contribute to the capacity for cell replication by compensating for telomere loss. Exploring the use of different cytokine combinations in increasing cellular replicative potential through telomerase activity may be useful for in vitro expansion of haematopoietic stem cells for transplantation. In this study, expansion of cord blood mononuclear cells was done in the presence of IL-3 and stem cell factor. Telomerase activity was assessed before and after one week of culture by a modified version of the telomeric repeat amplification protocol (TRAP). Cord blood samples expressed a basal level of telomerase activity which was increased in 80% of samples after expansion. However this increase did not reach a statistically significant level. The results of this work suggest that IL-3 and stem cell factor slightly increased telomerase activity of expanded cord blood cells. However, the addition of more cytokines to the culture might be useful to reach the optimal culture conditions allowing greater induction of telomerase activity and the generation of haematopoietic progenitor cells that retain their proliferative capacity.