Many of the legislations have stated that the criminal judge has the absolute authority to prove the legal validity of the evidences to ascertain the veracity of those evidences. One of the major flaw that can annul the validity of those evidences is when it is obtained under duress. In the introduction of this paper the researcher was trying to raise an important issue in this context which was represented by the following question: What is the impact of duress on the confession in the Omani criminal code? In order to solve the raised issue, the researcher utilize the descriptive analytical method throughout his paper, initially he elucidates the definition of confession as a one of the evidences in the criminal case. Then he explains the conditions to ensure the validity of any confession. Accordingly, he also explores the duress that forces the accused to confess against his will which consider as a reason to annul his confession since it breaches one of the conditions of valid confession which is the autonomy, therefore, the decision to grant the validity of such confession is made at the discretion of the court, which in turn decide whether to take that confession fully, partially or to completely reject the confession in the case. One of the cardinal results that the researcher attain from his paper is : The judicial confession can be considered as an evidence itself and consequently can be used as a verdict of guilty, and the reason to keep the confession under the estimate of the judge is only to ensure the practical validity of this evidence. All of that was mentioned clearly in the Article 191 of the criminal procedure law of the Omani criminal code which stipulated that the judicial confession is enough to judge based on it without the need for further evidence. Likewise, the modern pictures of duress considered as illegal even though there are no legislations to accuse it since it acts against the accused desire or will. As to the recommendations that the researcher came with in his paper, He recommend that, the legislations need to give the accused the right of self-defense in case he faced any risk from the authority during the investigations. In addition, the absolute criminal judge authority in the estimation of the evidences need to be restricted to meet the jurisprudence regulations. Moreover, the law needs to state clearly in the admissibility of taking confessions that deny the fault or the responsibility.