The present study was carried out in 26 viJlages at two Governates (Al-Khobah, and Haroob) in Jazan Region in Southwest Saudi Arabia to identify and detect the presence of Plasmodium in Anopheles arabiensis using nested-PCR technique. An. Arabiensis was identified by PCR and it was the predominant Anopheles mosquito in all the collection sites. A total of 257 An. Arabiensis females were collected and two samples from two villages (Almuatan and Alsabkha) out of 107 (1.87%) female mosquitoes from Haroob Governorate were found positive for the sporozoites of Plasmodium falciparum. Similarly, 3 out of 150 (2%) female mosquito samples from Um-alkhameir, AL-Khobah Governorate, were also found positive. Around fourfold increase of the sporozoite rate (from 0.61 to 2.0%) in An. arabiensis in Al-Khobah Governorate has been observed compared to the previous study of 2007-2008. The wide spread of An. arabiensis in Jazan region with >90% of the malaria cases caused by P. falciparum, along with infectivity rate ranges between 1.87 to 2.0% for P. falciparum in Al-Khobah and Haroob Governorates, suggests that P. falciparumn is the most predominant malaria parasite and An. Arabiensis is a very efficient malaria vector in the region. It also suggests more in-depth researches on the ecology, behavior, and control of An. Arabiensis to promote area-specific control programs.