blood from the umbilical cord is an alternative for the isolation and culture of cd34+ hematopoietic stem cells useful for bone marrow replacement therapy in the treatment of neoplastic and nonneoplastic pathologies. the expression of proteins related to the differentiation of cd34+ hematopoietic stem cells under culture was evaluated in this paper. the blood samples from the umbilical cord were collected in bags with cpda (baxter？) and transported to the hematology laboratory of the faculty of sciences of the pontificia universidad javeriana. the isolation of the cd34+ hematopoietic stem cells was carried out by using the miltenyi biotec microbeads？ system starting from mononuclear cells obtained by density gradient with ficoll-hypaque amershan biosciences？. the cd34+ cells were cultured in stem pro？ medium supplemented with il3, scf and gm-csf between 5 and 11 days at 37o c and co2 5 %. cellular viability was defined. the morphological changes were determined by inverted microscopy, whereas the expression of the cd34, cd33 and cd38 proteins, and of bci-2 and cd95 was identified by flow citometry. 6 cultures (n=6) enriched with cd34+ hematopoietic cells were established, with a viability average of 84.25 % and a culture time from 5 to 11 days. in the morphological evaluation, it was observed the appearance of cytoplasmatic prolongations or magnupodia-like pseudopodes until the seventh day of culture. the coexpression of the cd34 y cd33 antigens with an increase of cd95 protein from the seventh day on was observed. the cd34+ hematopoietic stem cells taken from the blood of the umbilical cord presented cytoplasmatic correlations that were possibly associated with cell to cell interactions. in our culture system, the obtained hematopoietic stem cells initiated processes of myeloid differentiation that were indirectly related to the expression of bci-2 and cd95.