IntroductionThe detection of adverse drug reactions has become increasingly significant because of introduction of a large number of potent toxic chemicals as drugs in the last two or three decades. Adverse drug reaction (ADR) monitoring and reporting activity is in its infancy in Mongolia. The important reason is lack of awareness and lack of interest of healthcare professionals in ADR reporting and documentation.GoalTo evaluate implementation and trends of health care professionals toward adverse drug reaction reporting at first, second and tertiary level hospitals.Materials and MethodA prospective study was carried out in first and second level hospitals of Khentii, Dundgovi, GoviAltai, Selenge and Uvurkhangai provinces, Sukhbaatar, Songinokhairkhan district hospital and First maternaty hospital. From tertiary level hospitals were selected First national hospital, Third national hospital, National center of oncolgy, National center of traumatolgy. The questionnaire survey involved total of 175 doctors and pharmacists.ResultsThe study result have shown that most of health care profeesionals (76 – 80%) of first and tertiary level hospitals have known about legal bases and theie duties for the ADR reporting than health care professionals (69%) of secondary level hospitals. And, pharmacists more activily involve in ADR reporting than doctors. The main reasons of healthcare professionals ADR underreporting were lack of time to report, lack of awarness about ADR and not knowing importance of ADR repoting. The implementetion extent of ADR reporting was in tertiary level hospital better than in secondary level hospitals. Lacking of clinical pharmacists and clinical pharmacologists and unproper activitity of Drug therapeutic committee in secondary level hospitals were the reason of poor implementing and underreporting of ADR.ConclusionThe study result has shown that there is needed to encourage doctors to the adverse drug reporting activity and implementation of drug safety should be strengthen in each level of health care system.