BACKGROUND: Age-related hormonal factors are thought to be related to the gender gap in longevity. Testing the hypothesis that survival is best in young premenopausal women we studied the effect of age on 1-week mortality in stroke patients. METHODS: A registry was started in 2001 with the aim of registering all hospitalized patients in Denmark. The patients' risk factors, stroke severity and CT scan were evaluated. A total of 25,607 patients (63%) gave complete information on all risk factors and were used in the analysis. Independent predictors of survival were identified by means of multiple logistic regression. RESULTS: The probability of death within 1 week adjusted for stroke severity, stroke type and risk factors was highly age-dependent in both men and women. Up to the age of 50 years, the 1-week female/male mortality rates paralleled being slightly (15%) but insignificantly better in women. While mortality increased almost linearly in women over the entire age range, it increased steeply in men from the age of 50 and at the age of 80 years survival was 80% better in women. CONCLUSION: The female stroke survival advantage applies to all ages. It increases with age due to a steeply increase of mortality in middle-aged and elderly men.