<p>Background: This study was aimed to assess the effects of angiotensin II (Ang II) supplementation to the In Vitro Maturation (IVM) and In Vitro Culture (IVC) media of vitrified-warmed ovine oocytes on their developmental competence and expression of Na⁺/K⁺/ATPase in resulting embryos.<br /> Methods: The slaughterhouse-derived immature oocytes (n=1069) were randomly distributed into four experimental groups: groups I and II) IVM/IVF and IVC of fresh and vitrified oocytes without angiotensin supplementation (Control-Fresh and Control-Vit groups, respectively); group III) IVM of vitrified oocytes in the presence of Ang II followed by IVF/IVC (Vit-IVM group); and group IV) IVM/IVF of vitrified oocytes followed by IVC wherein the embryos were exposed to Ang II on day 4 of IVC (Vit-D4 group). The embryos were immunostained with primary antibodies against Na⁺/K⁺/ATPase &alpha;₁ and &beta;₁ subunits.<br /> Results: In Vit-IVM and Vit-D4 groups, the rates of expanded and total blastocysts on day 7 as well as the proportion of blastocysts on day 8 were increased. The expression of Na⁺/K⁺/ATPase &alpha;1 and &beta;₁ subunits were positively influenced by the addition of Ang II on day 4 (Vit-D4 group).<br /> Conclusion: The addition of Ang II to the IVM and IVC media could improve blastocysts formation in vitrified sheep oocytes. This improvement might be related to the greater expression of Na⁺/K⁺/ATPase &alpha;₁ and &beta;₁ subunits when Ang II was added during IVC.</p>