We thank all researchers and collaborators in the field who have contributed to the work on monitoring of forests in the Republic of Serbia, and the scientific contribution of this paper. In particular, we emphasize the good cooperation between scientific research and educational institutions in the field of forestry, which worked on the research - monitoring the state of forests in the Republic of Serbia. The Paper presents the results of the National Focal Centre for forest condition monitoring in the Republic of Serbia on Level I and Level II plots due to ICP Forest Program. The total number of the installed sample plots on the area of the Republic of Serbia is 130 sample plots. . According to ICP Forests Manual, crown condition assessments are mandatory on all plots once a year, soil condition assessment every ten years, as well as the assessment of nutrition condition of forest trees foliar analysis. Monitoring on the Level II sample plot was implemented continuously in accordance with the instructions for forest monitoring. Assessment of tree crown condition on the Level II sample plots includes assessment of a greater number of mandatory parameters. Mandatory p