The feature of expertise of temporary disability is that expert decisions are considered according legislation as a basis of providing patients with various types of social protection and, in particular, exemption from work during acute period of disease. Since this is an issue of spending budget funds and extra-budgetary funds for these activities, all the procedures of expertise of temporary disability are regulated by legislative and regulatory acts that not always clearly define actions of doctors in various situations, and sometimes do not correspond to constantly changing conditions in the system of medical organizations functioning. The recent alterations in the legislative base led to a significant increase of burden on medical commission of the prolongation of medical certificates, which was already high enough due to appeals related to referral of patients to medical social expertise, medical examination of citizens, etc. The article presents the analysis of medical commission functioning of a large hospital-polyclinic association related to prolongation of medical certificates. The authors pursued the goal of identifying unfavorable trends in the medical commission functioning and identify ways to optimize it. The assessment of current status of the medical commission functioning demonstrated that prevention of injuries, especially domestic ones, as well as prevention of exacerbations of chronic diseases, including within the framework of dispensary observation of corresponding contingents of patients are of great importance for reducing the temporary disability of citizens.