The Danish National Prescription Registry (NPR) is a comprehensive resource for pharmacoepidemiological research, providing over 20 years of nationwide coverage. Established in 1994, the NPR includes detailed information on all prescriptions redeemed in Denmark, including those for nursing-home residents. The registry is accessible to researchers through Statistics Denmark and the Danish Health Data Authority, offering anonymized data for well-defined research projects. Key strengths of the NPR include its extensive coverage, national scope, and inclusion of drugs used by nursing-home residents. However, it lacks data on indication, intended duration, and dosage, which can be a limitation in certain studies. The NPR is compared with other Danish and Nordic prescription registries, highlighting its unique features and limitations. The registry's data quality is generally high, with validation studies showing a high degree of completeness. Despite some limitations, such as the lack of data on over-the-counter drugs and potential misclassification due to original pack dispensing, the NPR remains a valuable tool for studying drug utilization, treatment quality, and long-term exposure to medications.The Danish National Prescription Registry (NPR) is a comprehensive resource for pharmacoepidemiological research, providing over 20 years of nationwide coverage. Established in 1994, the NPR includes detailed information on all prescriptions redeemed in Denmark, including those for nursing-home residents. The registry is accessible to researchers through Statistics Denmark and the Danish Health Data Authority, offering anonymized data for well-defined research projects. Key strengths of the NPR include its extensive coverage, national scope, and inclusion of drugs used by nursing-home residents. However, it lacks data on indication, intended duration, and dosage, which can be a limitation in certain studies. The NPR is compared with other Danish and Nordic prescription registries, highlighting its unique features and limitations. The registry's data quality is generally high, with validation studies showing a high degree of completeness. Despite some limitations, such as the lack of data on over-the-counter drugs and potential misclassification due to original pack dispensing, the NPR remains a valuable tool for studying drug utilization, treatment quality, and long-term exposure to medications.