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This study assessed the efficacy of the Ovsynch protocol vs the classical cronolone containing vaginal sponges - eCG treatment in order to apply fixed-time artificial insemination (AI) in high yielding dairy ewes during the breeding season. Seventy seven ewes of Lacaune breed, 2-5 years of age, 3-3.5 body condition score and mean yield of 2.5 kg/ewe/day were randomly divided into 2 groups. In group 1 (n=38) estrus synchonization protocol consisted of an initial administration of a 1 ml GnRH analogue (Receptal®, MSD Animal Health, USA) followed 5 days later by a 0.5 ml prostaglandin F2α (Estrumate®, MSD Animal Health, USA) administration. Forty eight hours later a second dose of 1 ml GnRH (Receptal®, MSD Animal Health, USA) injection was given to synchronize ovulation. In group 2 (n=39) estrus synchronization was based on treatment with 30 mg flugestone acetate (Chronogest® CR, MSD Animal Health, USA) intra-vaginal sponges followed by an intramuscular injection of 500 ml eCG (Intergonan®, MSD Animal Health, USA) on the day of sponge withdrawal. Onset and duration of estrus were determined using an aproned male. Ovsynch-treated ewes were inseminated at pre-determined times 12 h and 36 h after the second GnRH injection. Flugestone acetate –eCG-treated ewes were inseminated at 48 h and 72 h after sponge removal. Pregnancy was diagnosed 42 days after AI using an ultrasound scanner (Draminski® Animal Profi 2) equipped with a 5 MHz linear-array transducer. Results show that 78,9% of ewes of group A exhibit estrus activity versus 100% in group B (P<0,01). Lambing rate in group A (47.22 %) was lower compared to group B (64.86%). However the difference was not significant (P>0.132). A significant difference was noticed in the lambing period between the two groups (P<0.01), with the period of A group to be expressed in lower value. In group A litter size (P>0.269) and fecundity (P>0.132) were not significant compared to group B. In conclusion, during the breeding season, and in high yielding dairy ewes, the Ovsynch protocol may be a potential alternative to the conventional long term protocol of flugestone acetate–eCG treatment.