Randomized controlled trials (RCTs) are still the «gold standard» in hierarchy of evidence-based medicine. RCTs are characterized by strict inclusion and exclusion criteria. On the one hand, this minimizes the risk of uncontrolled factors (systematic errors) affecting subsequent results. On the other hand, this limits application of the obtained results to the entire population. Indeed, certain groups of patients that are present in real clinical practice do not pass the strict inclusion and exclusion criteria for RCTs. Medical registries complement the information obtained in RCTs, provide objective data on efficacy and safety of therapy in patients who were not included in RCTs. In addition, registries ensure invaluable information if RCTs are not ethically feasible and have an important control component of the results obtained in previous RCTs. The article presents the goals, objectives, advantages and limitations, as well as methodological aspects of medical registers. The authors analyzed the opportunities of registries for clinical practice using the RIETE registry as example. The RIETE Registry is a prospective observational study aimed at treatment options for venous thromboembolic complications (VTEC) regarding assistance in medical decision making, reducing mortality, VTEC recurrence and bleeding. One of the important objectives of the registry is development of a primary patient record. It ensures consistent data collection across all patients included in the registry. As an example, the authors developed and proposed in-hospital record of a patient with pulmonary embolism (both with and without deep vein thrombosis) for a registry study. This record may be useful in planning new studies. The record is consistent with modern clinical guidelines and based on analysis of international registers and physician survey data.