According to the traditional understanding of the Federal Supreme Court (STF) state enterprises are subject to two procedural regimes of judicial enforcement by certain amount, taking as the criterion of choice - one or the other - the core activity that the entity carries. Thus, if the debtor entity has as primary function providing public services, the procedural prerogatives of the Public Administration are extended to it, enabling the execution of the writ by the regime settled by the articles 730 and 731 of the Civil Procedure Code (CPC), while the state entity that explores economic activity is subject to the common judicial enforcement regime applied to the private enterprises, submitted to the provisions of the Book II of the CPC. However, there are state-owned enterprises in Brazil performing both activities simultaneously, such as the Brazilian Post and Telegraph Company (ECT). It happens that the Supreme Court, in analyzing which legal regime of judicial enforcement is applicable to the ECT, simply described the entity as a provider of public service, which is why the privilege of immunity over property, rents and services was applied, determining the incidence of the scheme of precatory. In this context, this research aims to question the position adopted by the Supreme Court regarding the legal regime of judicial enforcement for certain amount applicable to state enterprises that simultaneously provide public service and explore economic activity, indicating the need for a revision of the understanding shown by the Court and suggesting a more consistent solution with the peculiar legal status of state enterprises in this condition, using as a paradigm the ECT.