This study estimate the effect of C-Type Natriuretic Peptide (CNP) on quality of ram's epididymal sperms and the rate of fertility in ewes inseminated artificially with CNP-treated and not-treated sperms. Initially, a total of 20 testicular samples were collected, processed to obtain the epididymal sperms, and then divided into two groups; the 1^st that treated with the suitable dose of CNP (0.01 ´ 10^-13) and the 2^nd was act as a control (not-treated with CNP). Semen samples of both groups were tested using the turbidimetric analysis. Also, an overall 10 adult ewes were selected, acclimated, subjected to estrus synchronization, and then divided equally into two groups to be inseminated artificially with only epididymal sperms and CNP-treated sperms. The findings of turbidimetric analysis revealed the significant decreasing in values of lag time of CNP-treated sperms (3.11 ± 0.26) when compared to control (6.46 ± 1.48). The results of motility index of both CNP-treated sperms (0.222 ± 0.034) and control (0.247 ± 0.069) were differed insignificantly. Significant elevation in values of velocity (P<0.011) was reported in CNP-treated sperms (0.399 ± 0.048) than the control (0.208 ± 0.098). Also, FRMS of CNP-treated sperms (0.028 ± 0.0063) was increased significantly when compared to control (0.019 ± 0.0047). Using the ultrasonography, the findings of artificial insemination recorded that the pregnancy rate after 2 months was 0% (0/5) in ewes inseminated with only epididymal sperms and 40% (2/5) in ewes inseminated with the CNP-treated sperms. In conclusion this represents the first Iraqi study targets the effect of CNP on ram's epididymal sperms and the role of CNP in increasing the fertility rate in ewes. However, changes occur due to excessive exposure to CNP remain unclear recommending moreover studies As well as, the toxicological profile of CNP must be known during utilization of CNP with the semen or as a dietary supplement to increasing the fertility.