Al Zoubi MS, Al-Batayneh K, Alsmadi M, et al. - In this preliminary study, semen specimens of 120 asthenozoospermic infertile men and 80 normozoospermic individuals were obtained at the in vitro fertilization unit in order to examine the presence of 4,977-bp mtDNA deletion in asthenozoospermic infertile men in Jordan. Following the enrichment of spermatozoa, MtDNA was extracted, followed by a polymerase chain reaction done using 4,977-bp mtDNA deletion-specific primers. In comparison with 10% in normozoospermic controls, the deletion of 4,977-bp mtDNA was identified in 79.2% of asthenozoospermic individuals. The results revealed a notable relationship between the presence of 4,977-bp mtDNA deletion and asthenozoospermia and infertility. Therefore, in the Jordanian population, findings emphasized a strong correlation between 4,977-bp mtDNA deletion and asthenozoospermia.