Aims To investigate if gender bias is present in today's setting of an early invasive strategy for patients with acute coronary syndrome in Denmark (population 5 million). Methods and results We identified all patients admitted to Danish hospitals with acute coronary syndrome in 2005-07 (9561 women and 16 406 men). Cox proportional hazard models were used to estimate the gender differences in coronary angiography (CAG) rate and subsequent revascularization rate within 60 days of admission. Significantly less women received CAG (cumulative incidence 64% for women vs. 78% for men, P < 0.05), with a hazard ratio (HR) of 0.68 (95% CI 0.65-0.70, P < 0.0001) compared with men. The difference was narrowed after adjustment for age and comorbidity, but still highly significant (HR 0.82, 95% CI 0.80-0.85, P < 0.0001). Revascularization after CAG was less likely in women with an HR of 0.68 (95% CI 0.66-0.71, P < 0.0001) compared with men. More women (22%) than men (10%) (P < 0.0001) had no significant stenosis on their coronary angiogram. However, after adjustment for the number of significant stenoses, age, and comorbidity women were still less likely to be revascularized (HR 0.91, 95% CI 0.87-0.95, P < 0.0001). Conclusion Women with ACS are approached in a much less aggressively invasive way and receive less interventional treatment than men even after adjusting for differences in comorbidity and number of significant stenoses.