Equality of litigants is considered one of the fundamental principles and one of the basic and necessary issues for the fair handling of lawsuits, and the Civil Procedure Law of Iran and the Federal Civil Procedure Law of the United States, one of which is derived from Islamic jurisprudence and law and from the type of system centralized proceedings and others that are subject to the common law system and a decentralized judicial system, in some cases they have considered the principle of equality and equal defense possibilities for litigants and some of the articles related to civil proceedings in these two countries, based on the principle Equality of litigants in civil proceedings and in order to guarantee compliance with the mentioned principle, the principles and rules governing civil proceedings, including the principle of equality of litigants in the legal system of Iran and America, have been compiled with global and regional international documents. Human rights are compatible. Regarding administrative proceedings, in Iranian law, there are no codified provisions on administrative proceedings, and the principle of equality of litigants can be achieved through scattered provisions and the law of the Administrative Court of Justice. In American law, which is basically a centralized judicial system, the principle of equality of litigants in administrative proceedings is also recognized.