This article is one in the set of publications about the different types of procedural estoppels used in the Russian judicial practice. The main goal was the estimation of the positive potential, which the doctrine of estoppel might have for the development of the Russian Law of Civil Procedure. In the present research two subjects were scrutinised: the correlation between procedural estoppels and the principle of good-faith and the use of estoppel instruments against the late presentation of procedural materials before the court. In the first part of the article authors draw a conclusion that procedural estoppel,taken as a whole, should be deemed as an instrument, by which the corrective function of the good-faith principle operates. This instrument helps to soften the strict operation of the procedural law, where it contradicts the aim to organize the execution of justice in the rational and most effective way.