Source rock is one of main elements in petroelum system. In order to investigate a petroleum system in an oil region, it’s necessary to recognize the characteristics of source rocks. In this study the source rocks of the Darkhovain oil field in Abadan plan are investigated. In this way, gamma rays and sonic log are used and source rock zones separated in Pabdeh, Garu, Gotnia, Najmeh, Sargelu and Nyriz formations. These zones sampled and total organic carbon of samples determined with Rock Eval analysis. Acording to Rock Eval results, Sargelu and Garu zones have good to excellent total organic carbon and good to moderate genetic potential. These zones have more thickness then the other zones. Kazdumi source rock samples show range of good to very good in total organic carbon and a range of moderate to good in genetic potential.