Recent studies have suggested that patients with idiopathic dilated cardiomyopathy (IDCM) who smoke have an improved prognosis as compared with nonsmokers. We examined this paradoxical finding using data from a population-based study in Washington, D.C. (n = 127). Current smokers were more likely to have a left-ventricular ejection fraction (LVEF) of 25% or greater as compared with IDCM patients who were past smokers or lifelong nonsmokers (p < or = 0.02). The cumulative survival among current smokers at 12 and 24 months was 88.1 and 81.4%, respectively, as compared with 77.9 and 71.6% among past smokers and 74.0 and 64.3% among patients who had never smoked. In a univariate analysis using the proportional hazards model, lifelong nonsmokers and former smokers were about twice as likely to die as compared with smokers, although the association was not significant (p > 0.10). In multivariable analysis, older age, LVEF, and ventricular arrhythmias - but not cigarette smoking-were found to be statistically significant independent predictors of survival (p < or = 0.05).