This study concerns measuring the quality of health services in long-term residential mental health care. The issue of measuring the quality of health services has been limited to services at residential health care centers (ZOL). The aim of the study is to propose measures associated with the provision of services in long-term residential mental health care. Currently, there are no tools for measuring the psychiatric services provided. The consequence of that isthat the monitoring-supervisory-control mechanism that should ensure the required level of quality of services provided in this area of psychiatric care is inefficient. The aim of the deliberations made in this study is presenting an appropriate set of measures to assess the performance of aresidential health care provider, taking into account the specificity of long-term mental health care (ZOL). The application of the Team Patient Functioning Scale allows for the specification of the changes occurring in the patient’s functioning and comparing them at time intervals, and indirectly causes the Team Patient Functioning Scale to be used to draw conclusions about the aggravation, stabilization, or regression of the illness, and to prove the effectiveness of the therapeutic team. The presented results of the application of the proposed measures may constitute a reference base – as a benchmark – for the improvement and development of the quality of health services for patients in residential health care centers in Poland.