This article studies the practice of predetermined choice of suppliers in public procurement in post-socialist countries. The authors conducted an online survey of suppliers in Russia and Slovakia in 2020, revealing that, despite different models of procurement regulation, this practice was being widely used in both countries. Some were justifying predetermined choice to guarantee delivery and quality. Surprisingly, Russian suppliers assessed the efficiency of public procurement higher than Slovak suppliers, which can be explained by more efficient monitoring and conflict resolution via the courts. The authors conclude that Slovakia possesses an insufficient level of monitoring and law enforcement in public procurement. This article contributes to the literature on procurement efficiency by emphasizing the crucial role of monitoring and law enforcement rather than regulation. © 2022 Informa UK Limited, trading as Taylor & Francis Group.