In vitro maturation (IVM) of immature oocytes is a promising technique to reduce the costs and avert the side effects of gonadotropin stimulation in in-vitro fertilization (IVF). Cryopreservation of immature oocytes followed by IVM technique can offer advantages, such as to avoid the use of large doses of gonadotropins for multiple follicular growth and induction of ovulation. Objective The objective of this study was to investigate the effects of two methods for immature oocyte cryopreservation on successful rates of in vitro maturation using several biochemicals. Materials and Methods In the present study, 674 immature oocytes were examined for viability and morphology directly post-aspiration from sheep ovaries. After that, normal and viable immature oocytes were divided into three major groups including: (213) for control group, (253) for vitrification technique and (208) for rapid cryopreservation technique. Post-thawing, each major group subdivided into four in vitro maturation (IVM) groups using SMART medium with special additives involving: (G1) group: contained gonadotropins (Gn) only, (G2) group: supplemented with Gn and sucrose (4%), (G3) group: consisted of Gn, sucrose (4%) and follicular fluid (FF) (5%), and (G4) group: contained Gn, sucrose (4%) and FF (10%).Then, assessment the results of in vitro maturation, viability and morphology of the oocytes