There are very few contemporary studies on the frequency and cause of congestive heart failure (CHF) in a general population. In western Sweden, inhabited by 1.64 million people, a retrospective survey was performed. All hospital records of patients with CHF, ages 16 through 65 years, were examined in all hospitals in the region. During the study period 2711 patients fulfilled the criteria for CHF or cardiomyopathy. Patients were monitored for 37 +/- 28 months. The most common cause of heart failure was coronary artery disease (IHD) (40%). Other common causes were hypertension (17%), valvular disease (13%), alcohol (11%), diabetes mellitus (10%), and systemic diseases (10%). There were positive correlations between the male sex and IHD, alcohol, and dilated cardiomyopathy; the female sex was associated with systemic diseases, valvular heart disease, and diabetes. The incidence of CHF requiring hospitalization per 100,000 in the population was 1.2 to 263 men and 1.1 to 129 women, in the youngest (age 16 to 30 years) and oldest (61 to 65 years) age groups, respectively. The 5-year survival rate was 50%. Analysis of causes performed with Cox's proportional hazards model for survival showed that age, IHD, alcohol, and diabetes were independent and powerful predictors of mortality (p < 0.001). The mode of death was progressive heart failure in 54% and sudden death in 26%. We concluded that the prognosis in patients with CHF was still very poor, even among this young population. The most common cause of CHF was IHD, and the second was hypertension.