From June 1, 2015, Article 3271 “Conditional fulfillment of the obligation” was introduced into part one of the Russian Civil Code. At that time, Russian civil law recognized only the right of the parties to make the emergence of rights and obligations in the obligation dependent on the occurrence or non-occurrence of a condition, regarding which it is not known whether it will come or not (Article 157 of the Russian Civil Code). Since June 1, 2015, the opportunity has been legalized to determine the dynamics of an obligation – its fulfillment, that is why there is a necessity to study the concept of “conditional fulfillment of the obligation”, its interpretation and definition of its essence. The aim of the research is to determine the legal nature of the “conditional fulfillment of the obligation” based on the normative definition, as well as the meaning of this concept, given by judicial practice. To achieve this aim, the following tasks were set: to analyze the normative content of Article 3271 of the Russian Civil Code, to consider “conditional fulfillment of the obligation” through the exercise by the authorized entity of its secondary right to refuse to execute the contract, as well as through the construction of transactions in which the exercise of the right and the fulfillment of the obligation the parties are simultaneously interdependent and dependent on the onset of some external circumstance (condition). The research methodology is based on the methods of scientific knowledge – analysis, synthesis, historicism. As a result of the research, it was concluded that in the legislative construction “conditional fulfillment of the obligation” there are signs of an independent type of obligation with conditional fulfillment, the prerequisite for the emergence of which is the agreed will of the parties to make the moment when the entitled party exercises his right of claim and the obliged party fulfills his obligation depending on the occurrence or non-occurrence of the condition. It also considers the issue of the possibility to condition the exercise by the entitled party of the secondary right, which is possible in the construction of an obligation with conditional fulfillment.