Abstract: This study was designed to investigate effects of natural mating versus artificial insemination in ewes synchronized for estrus/ovulation by single versus double sponge inserts combined with PMSG. A 120 cyclic Herri ewes were utilized in the study. The 10 ewes served as control (C), given no treatment, 58 ewes were designed to be naturally mated at estrus exhibition, 47 of which were inserted with a single sponge impregented in Fluoro Gestone Acetate (FGA) for 12 days and given 500 IU PMSG at sponge removal (SSNM-G1) and 11 ewes were given Double Sponges (DSNM-G2), the 1st sponge lasted 7 days, removed and replaced by a 2nd sponge for 5 days and at the 2nd sponge removal 500 IU PMSG was given (i.m). All ewes were visually observed for estrus signs and at onset of estrus, fertile rams were allowed to mate ewes. Time from sponge removal until estrus exhibition was recorded for each group. The artificially inseminated ewes were randomly allocated into 2 group, SSAI (G3, n = 31 ewes) and DSAI (G4, n = 21 ewes) in which ewes were given a single and double sponge inserts, respectively. Animals in G3 and G4 were timed inseminated with chilled fertile semen 48-50 h after sponge removal. All ewes were diagnosed for pregnancy 30 days post breeding by ultrasound. Proportion of ewes observed in estrus was highest in DSNM ewes (100%), followed by SSNM (91.5%) compared with C ewes (70%). Mean time interval from sponge removal till estrus was shorter in DSNM (38.1 h) than in SSNM (46.3 h). Likewise, conception and pregnancy rates were higher in DSNM (81.8 and 81.8%, respectively) than in SSNM (74.4 and 68%, respectively). Artificial insemination resulted in lower pregnancy rate (42.3%) with 35.4% in SSAI and 52.3% in DSAI ewes. Mean pregnancy rate in control ewes was 50%. In conclusion, inserting 2 sponges throughout 12 days combined with 500 IU PMSG at sponge removal shortened the interval from sponge withdrawal till exhibiting estrus, increased conception rate and pregnancy rate in Herri ewes.