Subject. The article discusses the need for methodological support and technological justification of assessment and improvement of the customs services quality at the post-customs control stage. Objectives. The study aims to develop a comprehensive methodology to evaluate the effectiveness of structural units and the quality of rendered services as a basic element of the management mechanism. Methods. The study rests on the system methodology. We decomposed the mechanism of customs services quality management, and developed its morphological model during the analysis of individual components of the mechanism. Results. We developed a mechanism to manage the quality of services provided at the stage of post-customs control. It is divided into operational and strategic levels of management decision-making. Furthermore, we disclosed individual elements of the quality management mechanism, identified the main activities of the post-control units, within which key performance indicators are evaluated. As a pragmatic example, we developed a matrix for calculating performance indicators for one of the main areas of activity. Conclusions. The further direction of scientific research should be a model of the consumer of customs services, which determines the economic essence of solving the problem of developing the activities of the Federal Customs Service of Russia at the stage of post-customs control.