In Rhodnius prolixus egg production is very important for embryonic development and specie perpetuation. In insect eggs, a phospholypoglycoprotein, vitellin (VT) constitutes the major protein in the so called yolk granules. VT is made of three distinct populations called VT1, VT2 and VT3 (Salerno, 1996). These populations come from different destinations sites: VT1 is more externally located in the oocytes; VT2 at the central region of the oocyte and VT3 in an intermediary position.  Western blots demonstrate that VT1 is a monoubiquitinated protein. This characteristic may have an important role in its destination to specific yolk granules inside the oocytes. It is also demonstrated, by imunofluorescense, that ubiquitinated yolk granules are located more externally in the oocytes. However, when we observed the yolk bodies, only the smaller ones are ubiquitinated.  This localization of ubiquitin in oocytes is very similar to that of VT1, when uptaked by the oocytes (Salerno, 1998). Besides, the development of R. prolixus embryo is initiated in the yolk cortex. Analyses of ubiquitinated-VT during embryogenesis suggest that VT1 disappears during the initial phase of embryogenesis. The remaining VT seems to be re-ubiquitinated during the mid-phase. The possible function of ubiquitination and   re-ubiquitination of VT will be discussed. Moreover, we also demonstrated that VT1 is produced by the follicular epithelium, ubiquitinated, and released to be uptaked by the oocyte, through a pathway yet unknown in cell biology. In this study it is also demonstrated the existence of a deubiquitinase associated with the fraction of VT1, which might constitute an important tool to determine the role of ubiquitination of VT1 in the oocytes of Rhodnius prolixus.