OBJECTIVES: Adverse drug reactions (ADR) in hospital are a significant cause of morbidity and mortality. The aim is to analyze the ADR which have been collected through doctors’ and medical technicians’ spontaneous reporting. METHODS: The prospective study covered 655 patients hospitalized in Cardiology Center of Clinical Center of Montenegro. ADR were collected by spontaneous reporting. According to the criteria of World Health Organization, for every ADR causality assessment, severity, type, outcome, level of intervention and place of manifestation of ADR was established. RESULTS: In the 6 month period of research at the Cardiology Center, 655 patients were hospitalized with the average age of 60.72±11.36 years. With spontaneous reporting, 22 patients had 22 ADR which were noted. Doctors reported a statistically significant larger number of ADR (68%) than medical technicians (32%), p<0,01. Nine patients (41%) had serious ADR with the following outcome: 21 ADR were the cause of the hospitalization (22%), four ADR resulted in the extended hospitalization (44%), and 3 were life threatening (33%). The most frequent serious ADR were reported spontaneously by doctors and medical technicians and were caused by streptokinase (33%). The most frequent symptoms which the patients had as a consequence of ADR were: fainting (27%), headache (18%), weakness (14%), vertigo (14%) and vomiting (9%). CONCLUSIONS: Considering increased use of cardiovascular drugs and limitations in pre-marketing trials for drug safety evaluation, post marketing evaluation of adverse drug reactions induced by this class of medicinal products seems necessary.