The Persian Gulf has a history of more than four thousand years in the region and the world. The term has been used in all languages from Pythagorean up to 1958. Therefore, this study examines and identifies the name of Persian Gulf on maps and atlases in the National Library and Archives of IR.IRAN and Foreign Affairs Ministry Library. This study is fundamental and has used historical method. The study sample consisted of 14826 maps and 174 atlases in two libraries among them 689 items in National Library and 161 items in Foreign Affairs Ministry were investigated. Descriptive statistics is used to analyze the results.Results indicate that the name of the Persian Gulf on the Persian maps (49.3 percent), English maps (12.2 percent) and French maps (4.7 percent) is used The name also is used on atlases in the Persian language (25.3 percent), English (30.5 percent) and French (12.1percent) relating to the Middle East, Europe and America. This name has the highest frequency in 14th century (solar calendar=15 lunar calendar) and 20 & 21A.D.3 percent of the maps and atlases in two Libraries belong to the 12 A.D century or published before it. Among total of 689 items in the National Library and Archives Organization of the Islamic Republic of Iran 74.4% were maps, and 25.3%were Atlases. Among them 358 items (54.4%) were in Persian. Except 4items with Arabian Gulf on them, all of the other items consider the name of Persian Gulf.4 mentioned items belong to Middle east region that have used the Arabian Gulf in 1861, 1966, 1980 and 1993. One item which is published in Europe in 2003 has used the name “Gulf”. Among total of 161 items of Foreign Affairs Library, Persian Gulf is used 100 percent on them. The names that are used are: AlKhalykh Alfarsy, Bushehr Sea, Persian Gulf, Persian Gulf Trail Golf, golf persique, persischer gulf, golfo persico, sinus persicus etc. According to the research findings, the name Persian Gulf has a historical authenticity, and current false name has no historical root.