The requirements of measurement and accounting disclosure for investment in joint ventures in accordance with the Iraqi local system and rules differ from IAS. Local rules require events and conditions for accounting recognition that differ from IAS. Also, the adoption of IAS leads to achieving comparability between the financial statements of companies. Since the data provides many parties, including investors, with the necessary support in the investment decision-making processes, there is a difference in decisions due to the difference in those methods adopted in measurement and disclosure. The current study aims to find out what investment in joint ventures is in the accounting literature and to identify deficiencies in measurement and disclosure of investment in joint ventures in accordance with the unified accounting system and local accounting rules in comparison with the relevant IAS. The research concludes that there are shortcomings in the unified accounting system and local rules compared to IAS and the treatments and accounting methods adopted in it. The current study also provides recommendations, the most important of which is the need for units to prepare accounting statements according to the competent IAS and conduct comparison with the financial statements prepared in accordance with local regulations, because of the impact of this comparison on investment decisions, taking into account the laws in the Iraqi environment.