Purpose: The purpose of this research is to identify the accounting treatments for drilling and development expenses in the Iraqi oil companies according to the unified accounting system, and to indicate the extent of compatibility and difference in the treatment of drilling and development expenses between the unified accounting system and the International Financial Reporting Standard IFRS 6. Theoretical framework: The oil industry includes many activities and operations, starting from research and exploration operations through drilling and development operations, and ending with extracting oil from the well and delivering it to the consumer or transferring it to the refining industry. During these activities expenses are realized that should be accounted for in a way that ensures compliance with international standards for the oil industry as Iraq particularly witness a great development in the oil industry represented in dealing with foreign oil investment companies which means the need to standardize accounting treatments for the oil industry between local oil companies and foreign oil companies. Design/methodology/approach: The research used comparative descriptive approach by comparing the accounting treatment of drilling and development expenses under the International Financial Reporting Standard IFRS 6 and the unified accounting system applied in Iraq represented by the Basra Oil Company and the Iraqi Drilling Company. Findings: One of the most important findings of the research is the concord of the method used by the Basra Oil Company in capitalizing drilling expenses at the expense of wells under operation with the philosophy of the total cost method approved by the standard. However, this agreement is conditional on the absence of dry wells. If the drilling operations resulted in the presence of non-productive or productive wells but in uneconomical quantities, the treatment becomes not compatible with the standard. The practical and social implications: The Basra Oil Company treats all development (maintenance) expenses as operating expenses that are closed at the end of the year in the income statement, this it is not consistent with the philosophy of Standard No. 6 which states that development expenses that aim to maintain the production capacity of the well should be treated as operating expenses, but if development expenses that aim to increase the production capacity of the well must be capitalized on the cost of the well. Originality/ Value: The importance of the research comes from the need to work on applying the requirements of the International Financial Reporting Standard IFRS 6 in accounting treatments for oil expenditures, including drilling and development expenses in Iraqi oil companies.