Introduction: Sexual activity, combined with organic heart disease, may cause sudden death (SD). However, the causes of SD related to sexual activity are not known well. The aim of this study was to assess the causes of SD related to sexual activity. Methods: From August 2001 to December 2004, all autopsies performed at Kyungpook National University Hospital were reviewed in search of SD cases related to sexual activity. Since all the autopsies in the Taegu-Kyungpook region of Southeastern Korea were performed by pathologists from the Department of Forensic Medicine at Kyungpook National University, we had the opportunity to investigate the causes of SD related to sexual activity. Results: Eleven cases (45짹10 years old, 7 males) with SD related to sexual activity were found. All victims were heterosexual. The toxicologic study was negative in all subjects. Seven cases were witnessed; 5 cases occurred during sexual activity and just after in 2 cases. In 4 unwitnessed cases the victims were found dead in less than 8 hours from their sexual activity. In most cases SD occurred during the sexual act with a prostitute (n=3) or steady extramarital partner (n=7). The causes of the SD were as follows; coronary artery disease (CAD) in 4 (3 in male), subarachnoid hemorrhage SAH) in 4 (3 in female), fibromuscular dysplasia of the AV nodal artery (FMD) in 1, and unknown in 2. Conclusions; Coronary artery disease and subarachnoid hemorrhage were the most common causes of SD related to sexual activity.