AIMS: Results of previous studies on the influence of gender on prognosis in heart failure have been conflicting and most studies have been conducted in selected populations. The aim of this study was determine whether mortality risk in women and men hospitalized with congestive heart failure is different. METHODS AND RESULTS: Survival analysis of 5491 consecutive patients admitted with congestive heart failure to 34 Danish hospitals between 1993-1996. Follow-up time was 5-8 years. Forty percent of the patients were female. Females were older, had less evidence of ischaemic heart disease and their left ventricular systolic function was preserved to a greater extent than in males. Men were more often treated with ACE inhibitors. During the follow-up period 1569 women (72%) and 2386 (72%) of the men died. When the age difference between men and women was adjusted for, male gender was associated with an increased risk of death (RR 1.25 (1.17-1.34)) and the increased risk was confirmed in a multivariate model containing several covariates. CONCLUSIONS: In patients hospitalized with congestive heart failure male gender is an independent predictor of mortality. Female heart failure patients may be under-treated with ACE inhibitors.