BACKGROUND: Inherited disease may be causative in many young sudden unexpected death cases. Autopsy is essential in the counselling of the bereaved, as the family of the victim may be at risk too. In a nationwide setting operating under the same set of laws, we hypothesized that regional differences exist in the investigation of young persons dying suddenly and unexpectedly. METHODS AND RESULTS: All deaths in persons aged 1-35 years in Denmark in 2000-2006 were included. Death certificates were read independently by two physicians. External examination as well as autopsy status was retrieved. Significant regional differences were found regarding external examinations and autopsy frequencies. Ratios of conducted external examinations varied between 63% and 93% (p¿=¿0.004). Autopsy ratios varied between 60% and 88% (p¿=¿0.001). In urban areas, external examinations and autopsies were more often conducted than in rural areas. In East Denmark, there were more external examinations resulting in a forensic autopsy, and there was a higher overall autopsy rate compared to West Denmark. CONCLUSION: Despite operating under the same set of laws, we document significant regional differences in forensic investigations of young persons suffering a sudden unexpected death. This is probably not unique for Denmark although no data exist to confirm that. The results are worrying and call for a revision of the way these deaths are handled. Mandatory autopsy in sudden unexpected death in young persons is warranted as a thorough investigation of the death may help the clinician in guidance of the relatives in relation to hereditary diseases.