Introduction: Cause-specific mortality statistics is a valuable source for the identification of risk factors for poor public health.
Content: Since 1875, the National Board of Health has maintained the register covering all deaths among citizens dying in Denmark, and since 1970 has computerised individual records.
Validity and coverage: Classification of cause(s) of deaths is done in accordance to WHO's rules, since 1994 by ICD-10 codes. A change in coding practices and a low autopsy rate might influence the continuity and validity in cause-specific mortality.
Conclusion: The longstanding national registration of causes of death is essential for much research. The quality of the register on causes of death relies mainly upon the correctness of the physicians' notification and the coding in the National Board of Health.