BACKGROUND: Previous data have shown that various nonischemic cardiac diseases account for about 20% of sudden cardiac deaths (SCDs) and that dilated and hypertrophic cardiomyopathy (CM) are major causes of nonischemic SCD. OBJECTIVE: The purpose of this study was to define the prevalence and causes of SCD due to nonischemic CM in the current era given the substantial change in the diagnosis and treatment of cardiac diseases and in lifestyle patterns. METHODS: A total of 2661 consecutive victims of SCD from among a population of approximately 470,000 inhabitants in the Province of Oulu, Northern Finland, were included in the study. The causes of deaths were determined from the uniformly required autopsies of SCD victims in Finland, plus available medical records and standardized questionnaires. RESULTS: Nonischemic cause of SCD was found in 579 victims (21.8% of all the SCDs). Mean age (± SD) was 55 (±12) years; 78% were males. After subgrouping the nonischemic SCDs into various categories, SCDs associated most closely with obesity (23.7%), followed by alcoholic CM (19.0%), hypertensive CM (15.5%), and fibrotic CM (13.6%). Fibrotic CM was the most common association with SCD in subjects younger than 40 years (28.3%), whereas alcoholic CM was the most common cause of death in subjects between 40 and 59 years of age (25.8%). CONCLUSION: CM related to obesity, fibrotic CM, and alcoholic CM are commonly associated with nonischemic SCD in the current era. The association of SCD with fibrotic CM is notably frequent among victims younger than 40 years.