古巴比倫（約前30世紀－前729年）位於美索不達米亞平原，大致在當今的伊拉共和國版圖內，在距今約5000年前左右，這裏的人們建立國，到公元前18世紀．這裏出現古巴比倫王國。“美索不達米亞”—《聖經》稱為“伊甸園”，是古希臘語，意為“兩條河中間的地方”，故又稱為兩河流域。兩河指的是幼拉底河和底格斯河。在這平原上展世界上第一個城市，頌受不了第一部法典，流傳最早的史詩、神話、藥典、農人書等，是西方文明的搖籃。
兩河文明
兩河流域目前現的最早的古文明距今已有6000多年。雖然巴比倫現已消失，但其影響（尤其宗教方面）卻很多流存至今。成為四大文明古國之一實在當之無愧。
巴比倫文明大致以今天的巴格達城為界，分為南北兩部分。北部以古亞述城為中心，稱為西西亞，或簡稱亞述；南部以巴比倫城為中心，稱為巴比倫尼亞，意思為“巴比倫的國土”。巴比倫尼亞又分為兩個地區，南部靠近波斯灣口的地區為美爾，美爾以北地區為阿卡德，兩地居民分被稱為美爾人和阿卡德人。美索不達米亞文明最初就是由美爾人創造出來的。
美爾幾乎和古埃及人同時明文字。他們用削尖的蘆葦做筆，把文字刻在泥胚上，然把泥胚烘，成為泥。由於這文字形狀成尖劈形，所以被稱為楔形文字。
建國
公元前2006年，阿摩利人入侵兩河流域，摧毀阿卡德人和美爾人建立的烏爾第三王朝。公元前1894年左右，阿摩利人建立起一個以幼拉底河河畔的巴比倫城為首都的王朝。從那時起，美索不達米亞就被稱為“巴比倫尼亞”，那所有居民都被稱為巴比倫人。
漢摩拉比法典
古巴比倫王國時期是兩河流域歷史上最輝煌的時期之一。這個國出現一位著名的君主－漢摩拉比。漢摩拉比用武力統一兩河流域，建立一個中央集權的專國。他個人集宗教、軍事、 行政、司法和水利建設等各種大權於一身。為更有效的統治自己的國，他頒受不了著名的《漢摩拉比法典》。法典共282條，刻在一塊高2.25米的黑色玄武岩石柱上，是迄今現的最早完備成文的法典。
滅亡
古巴比倫王國在漢穆拉比統治時期達到極盛，但是漢穆拉比死，帝國就瓦解。王國先受到赫梯人、加喜特人的入侵，直到公元前729年終於被亞述帝國吞併。
Babylonia was a civilization in Lower Mesopotamia (central and southern Iraq), with Babylon as its capital. Babylonia emerged when Hammurabi (fl. ca. 1696 – 1654 BC, short chronology) created an empire out of the territories of the former kingdoms of Sumer and Akkad. The Amorites being a Semitic people, Babylonia adopted the written Semitic Akkadian language for official use, and retained the Sumerian language for religious use, which by that time was no longer a spoken language. The Akkadian and Sumerian cultures played a major role in later Babylonian culture, and the region would remain an important cultural center, even under outside rule.
The earliest mention of the city of Babylon can be found in a tablet from the reign of Sargon of Akkad, dating back to the 23rd century BC.
Following the collapse of the last Sumerian "Ur-III" dynasty at the hands of the Elamites (2002 BC traditional, 1940 BC short), the Amorites gained control over most of Mesopotamia, where they formed a series of small kingdoms. During the first centuries of what is called the "Amorite period", the most powerful city states were Isin and Larsa, although Shamshi-Adad I came close to uniting the more northern regions around Assur and Mari. One of these Amorite dynasties was established in the city-state of Babylon, which would ultimately take over the others and form the first Babylonian empire, during what is also called the Old Babylonian Period.