Fil: Crocco, Melisa Candela. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Parasitología; Argentina.Fil: Fratnz, Nilo. Reserach and Human Reproduction Center, Nilo Peçanha 1221, Porto alegre, RS; Brasil.Fil: Bos-Mikich, Adriana. Department of Morphological Sciences, ICBS, Federal University of Rio Grande do Sul, Porto Alegre; Brasil.Different laboratories around the world have succeeded in establishing human embryonic stem cell (hESC) lines. However, culture conditions vary considerably among the protocols used and the vast majority of the lines at some stage of their creation have been in contact with an animal derived component. One of the main problems to be overcome for the generation of a clinical-grade hESC line is the choice of a substrate and medium that allows derivation and culture, where animal derived components are kept to a minimum or completely excluded.