BACKGROUND There is a wide gap between the number of organ donors and patients on waiting lists for transplantation. The purpose of this Swedish nationwide study of the critical pathway for organ donation after brain death (DBD) was to identify missed opportunities for organ donation. METHODS We performed a prospective, observational study of all ICU deaths in Sweden from Jan 1, 2009 to Dec 31, 2014. The protocol structure followed the critical pathway for organ donation, which was developed and tested during 2008. We analysed differences in donation incidences between healthcare providers (counties) and patient characteristics using descriptive statistics and logistic regression. RESULTS The number of DBD per million population (pmp) was 14.9, varying almost 10-fold from 4.3 to 40.6 DBD pmp between counties. Regional variation in DBD decreased when we assigned the donor to the place of residence (from 6.9 to 27.7 DBD pmp). Women were more likely to become donors compared to men [crude odds ratio (OR) 1.60, 95% confidence interval (CI) 1.38-1.85, P < 0.001]. The increased likelihood remained after adjusting for age, comorbidity, and main diagnostic categories (OR 1.49, 95% CI 1.25-1.77, P < 0.001). An end-of-life decision was found in 50.9% of possible organ donors. CONCLUSIONS Regional differences in DBD were considerable, and women were more likely to become donors than men. There is a need for increased awareness of the potential for organ donation as an integral part of end-of-life clinical care. In-depth analysis of these differences may reveal opportunities for action that could lead to increased DBD.