The paper highlights the issues related to the concept of institutional reinforcement, both associated with endogenous institutional change and institutional reproduction as well as with other institutional phenomena. The concept of institutional reinforcement is analyzed through the prism of three relationships – between the institutions in the diachronic, between institutions and their carriers in the synchrony, between the counteragents while choosing a particular type of institution as a mechanism of regulation of transactions. For the characteristics of the first type of relationship we use the concepts of institutional reinforcement and quasi-parameters – endogenously varying parameters of the infinitely repeated game which directly do not cause the behavior of the players. Changes of quasi-parameters called by institutions may reinforce or undermine them. Reinforcement refers to the case when quasi-parameters changes lead to a self-sustaining behavior. For the characteristics of the second type of relationship is introduced a distinction between a standard type of agent – "economic man", motivated to achieve the economic goals, and a type, introduced as an alternative, known as "institutional man", acting under the influence of institutions and motivated to change his institutional position. The need to address to the third type of relationship occurs in a situation of institutional choice when economic agents are faced with the dilemma of which of the institutions or some combination of them prefer as a mechanism for implementation of the transaction. Examples of such a choice are the formal institutional mechanisms of contracts and informal ones of trust, which, being jointly used, can both reinforce and undermine the relationships of counteragents. Features of institutional reinforcement in all types of relationships are discussed in relation to the stationary and non-stationary economy, bearing in mind, above all, a Russian non-stationary economy.