This study's major aim is to investigate the situation of visceral leishmaniasis vectors, with a focus on their distribution and relationships to the disease in Iran and some other old-world nations. The terms Iran and the Old World, along with the keywords sand flies, vectors, visceral leishmaniasis, distribution, and Phlebotomus, were searched in electronic databases from 1930 to 2018, including Pub-Med, Web of Science, Google Scholar, and MEDLINE. According to the findings, Phlebotomus tobbi was a mountain species, but it was also found in the plains, rodent nests, and rock crevices. This species was considered to be one of the vectors of visceral leishmaniasis in Iran. Phlebotomus kandelakii has been caught in Afghanistan, Iran, Lebanon, Turkey and Georgia. In Iran, the first infection of Phlebotomus kandelakii and Ph. perfiliewi transcaucasicus with Leishmania infantum were reported in northwest of Iran. Phlebotomus major was one of the complex sand flies, and its members include Ph. major (India, Nepal, and Pakistan), Ph. neglectus (Southern Europe, Crimea and Iran), Ph. syriacus (Southwest Asia, Caucasus), Ph. notus (Afghanistan and Iran), Ph. wenyoni (Iran and Iraq), and Ph. wui (China). The first natural infection of Ph. alexandri with Leishmania infantum was reported in 2006 in endemic foci of visceral leishmaniasis in Fars Province, southern Iran. The findings of this project suggest that sand fly species of the subgenus Larrousisus play a key role in the transmission of all types of visceral leishmaniasis in Iran.