The plasmidic stability of methyltrophic yeast Pichia pastoris expressing the recombinant protein E of dengue virus 4 was analyzed. To this end, the number of generations from the growth process in petri plaque to the propagation in zaranda was estimated, as well as the fermentation process. Besides, in the selected colonies the integration pattern was determined by Dot-Blot and neuclotide sequence of the gene E of dengue virus 4. This study allowed to prove the conservation and integrity of the aminoacid sequence of protein E, despite the genetic changes produced by molecular yeast mechanisms. On the other hand, it was also part of the control and checking of the primary bank of yeast cells that contains the gene of interest used at present in the process of expression of protein E of dengue virus 4.