Accounting information that appear in the financial statements and reports is considered a very an important basis for the evaluation of company performance, a vital tool in designing their policies and making future decisions especially the decisions of investment in the market of securities on which is considered the essence of our study. This, of course, entails identifying and diagnosing this information and understanding it in order to employ and direct it in favor of decision makers as well as evaluating it to identify the points of strength and making use of them and the sensitive points and rectify them in an attempt to provide the best solutions that lead to promoting this job and supporting its status and role in rationalizing investment decisions in securities market. So, the problem tackled by this study is that many companies and investors in those companies are not aware enough of the importance of this information and that makes the decisions made – whether by the company management of investors are not sound especially in the field of securities and this makes their utilization limited. The study aimed at achieving a set of objectives, which are: Clarifying the concept of accounting information and its importance, identifying the reality of the accounting information provided by the financial statements and their preparation and use in rationalizing investment decisions concerning securities, manifesting the most important aspects of quality in accounting information that reflect their effectiveness and usefulness and promote the awareness about the importance of accounting information and employing it for the purposes of investment objectives. To accomplish the objectives of the study, a main hypothesis was adopted, which is: “accounting information with suitable good quality has a great role in rationalizing securities investment decisions”. To achieve the objectives of the study, the descriptive approach was used to construct the theoretical framework. While the practical aspect depended on the analytical approach by studying and explaining accounting information in the financial statements prepared by the contributing companies studied and comparing these statements. The study reached a set of theoretical and practical conclusions, most important of which are: 1. The availability qualitative characteristics of the accounting information makes it more suitable and more reliable to make rational decisions especially when it includes quality aspects in all the stages of their preparation such as artistic, practical, scientific, informative and ethical aspects. 2. Accounting information is considered a vital recourse for companies and a source of strength for them that support their competitive status in the market because it increase the awareness of the management staff of the financial status of companies and forecasting and planning their future. 3. The studied companies do not are not observe the preparation of cash flow statements although they are very important in identifying the operational and investment activities and they do not provide additional statements such as the periodic financial statements or the statements, which are prepared according to the current prices or according to the fair value. Also, they do not use computers in organizing and performing their financial aspects. 4. The results of studying and examination of the financial statements of the companies studied – including the descriptive and the quantitative information - showed that it provide good base of suitable and reliable information for the beneficiary parties, especially the investors. These results also indicated the availability of quality characteristics in that information but some of the requirements should be available to ensure the perfection of accounting information quality in them and consequently ensure their utilization in rationalizing investment decisions. This study has made a number of recommendations according to the mentioned conclusions such as: 1. The necessity of the complete complying with the accounting and standard rules issued by the accounting and observation standards council of in Iraq through the complete offer of the securities lists, particularly in the accounting expression of accounting knowledge outcomes relating with distributing the securities reports and lists and making them available for the users as well as supplying them with briefs about the most important information which are considered important for their decisions. 2. Encouraging those responsible for managing the companies to increase their knowledge and their performance of the accounting knowledge and guiding them to its importance and the importance of its managing and its effect on the investment decisions, and what are the necessary information through joining with developed training courses in order to increase their accounting knowledge as well as solving the modern information technology matters to ensure the speed and accuracy of the results.