Patient medical records and administrative healthcare databases are possible sources of real-world evidence (RWE), i.e., evidence on the potential benefits and risks of a medical product. RWE can complement the evidence from randomized clinical trials. The wide range of information collected by the National Health Fund (NFZ) and the Ministry of Health in Poland ensures the versatility of the data that cover almost all patients treated in Poland. In addition to administrative data (without detailed information about patients and their disease), electronic medical records of some patient groups can be obtained from special programs (e.g., KOS-Zawał) or the System of Monitoring Drug Programs (SMPT). Low usage (only 37 studies) but high usability of NFZ databases as a source of RWE were identified. Joint analysis of data from administrative databases and SMPT can increase the credibility of the study, but limits the study to only patients treated within the Drug Programs.