Asst. Lecturer Mohammed Hamza Idan College of Administrative Sciences – Department of Financial and Banking Sciences / Al-Mustaqbal University The preliminary investigation is considered a fundamental stage in criminal procedures, as it represents the link between the occurrence of the crime and the commencement of the trial. Its purpose is to collect evidence, uncover the truth, and determine criminal responsibility before referring the accused to the court. The Iraqi Criminal Procedure Code No. (23) of 1971, as amended, has regulated this stage with precision, taking into account the principle of legality as well as the guarantees of the accused and the rights of society. According to Article (51) of the law, the preliminary investigation in Iraq is conducted by an investigating judge or investigators under the supervision of investigating judges. They are the persons legally authorized to collect evidence, hear witnesses, interrogate the accused, and issue decisions related to detention or release. The authority of the investigating judge in this regard is extensive, yet it is restricted by legal safeguards aimed at achieving justice and preventing the abuse of power. Among the most important objectives of the preliminary investigation is uncovering the truth through the collection of material and moral evidence, identifying the perpetrator, and ensuring that criminals do not escape punishment, while also protecting the rights of the accused and preventing conviction except on the basis of lawful and legitimate evidence. The investigation also helps prevent the initiation of public prosecution without sufficient grounds, as it may reveal insufficient evidence, leading to the case being closed. The preliminary investigation in the Iraqi system is characterized by its written and confidential nature, in order to protect the reputation of individuals and ensure that the course of justice is not influenced. However, this does not prevent the presence of a defense lawyer during interrogation, confirming the right to defense established under Article (19/4) of the Iraqi Constitution of 2005 and international human rights conventions. In conclusion, the preliminary investigation is the cornerstone of the Iraqi judicial system, as the integrity and fairness of the entire judicial process depend on its soundness. The more the investigation adheres to the law and human rights standards, the more capable the judiciary becomes in upholding rights and achieving criminal justice in society.