One of the most common grounds of claims for annulment of regulations in the Administrative Court of Justice is their retroactivity. These lawsuits are based on the claim that a specific situation regarding a specific issue has prevailed in the past and the provision being objected to has made a change in it. Examining the decisions rendered by the General Board and the Specialized Boards of the Administrative Court of Justice shows that judgment regarding the retroactive claim of regulations is sometimes accompanied by challenges. The specific question that is addressed in this article is, in what circum+stances can we say that a regulation has become retroactive. The answer to this question, as the main goal of this article, which is written in a descriptive-analytical method, requires knowing the situations that can that serve as the basis of this claim.To understand these situations, it is necessary to pay attention to the time-frames in when the events in question occur and the change in the situation that governs them. There are three time-frames for events: past, current (composed of past and future) and future. The change of the situation governing events can also refer to the change of the situation in the past, current or future. Based on these categories, eight situations can be imagined. Each of these situations includes two set of circumstances: existence of a suitable opportunity to adapt to the new situation or its lack. Among the decisions rendered by the General Board and the specialized boards of the Administrative Court of Justice, more or less examples of these situations can be found, some of which are mentioned in this article.