Cardiovascular disease represents one of the most important public health problem in the Western countries, with sudden cardiac death (SCD) being the most common cause of death in adults under 65 years of age. The objective of the present study is to evaluate the leading causes of SCD in young adults who died suddenly in Northern Portugal between 2007 and 2012. This study included 288 cases of 20- to 45-year-old adults who died suddenly of a cardiac cause and whose forensic autopsy was performed in the North Branch of the National Institute of Legal Medicine and Forensic Sciences between 2007 and 2012. Data included the cause of death, forensic autopsy findings, previous medical history and cardiovascular risk factors. The mean age of the population was 37.36 years. Coronary artery disease (CAD) was the leading cause of death, representing 55.6 % of all cases (92.5 % of men and 7.5 % of women). Females died mostly from probable primary arrhythmia. From those who died of coronary disease, 72 (25 % of total cases) had histological evidence of a fatal acute infarction. Age, previous coronary disease, hypercholesterolemia, smoking habits and alcohol consumption seem to be associated with an increased risk of SCD by CAD. A total of 55.6 % of deaths were attributed to CAD. Prevention of cardiovascular risk factors should therefore be considered to prevent atherosclerosis in young adults.