Background: The first 2 days after childbirth present the highest risk of dying for a mother. Providing postnatal care within the first 2 days after childbirth can help avert maternal mortality because it allows early detection of problems that could result in adverse maternal health outcomes. Unfortunately, knowledge of the uptake of early postnatal care (EPNC), which is imperative for informing policies aimed at reducing maternal mortality, remains low in Uganda. Therefore, the purpose of this study is to investigate the determinants of early postnatal care attendance among Ugandan women. Methods: This study was based on nationally representative data from the 2016 Uganda Demographic and Health Survey. The study sample comprised 5471 women (age 15-49) who delivered a child in the 2 years preceding the survey. We used logistic regression to identify factors associated with use of early postnatal care. Results: Our findings showed that 50% of mothers used EPNC services for their most recent delivery in the 2 years preceding the survey. Women's residence, education level, religion, wealth status, marital status, occupation, antenatal care attendance, place of delivery, birth order, perceived accessibility of health facilities, and access to mass media messages were associated with greater use of EPNC. The percentage of women receiving EPNC was much higher among women who delivered at a health facility, either a public facility (63%) or private facility (65%), versus only 9% among women who delivered at home. Multivariate analysis showed that delivery at a health facility was the most important determinant of early postnatal care attendance. Conclusions: To increase mothers' use of EPNC services and improve maternal survival in Uganda, programs could promote and strengthen health facility delivery and ensure that EPNC services are provided to all women before discharge. Even so, the fact that only about two-thirds of women who delivered at a health facility received early postpartum care shows substantial room for improvement. Interventions should target women who deliver at home, women who attend fewer than four antenatal care visits, and women with a primary education.