- OSF HealthCare Saint Elizabeth Medical Center - Peru
- OSF Holy Family Medical Center
- OSF Little Company of Mary Medical Center
- OSF Sacred Heart Medical Center
- OSF Sacred Heart – Urbana
- OSF Saint Anthony Medical Center
- OSF Saint Anthonys Health Center
- OSF Saint Elizabeth Medical Center
- OSF Saint Francis Medical Center
- OSF Saint James - John W Albrecht Medical Center
- OSF Saint Katharine Medical Center
- OSF Saint Luke Medical Center
- OSF Saint Paul Medical Center
- OSF St Francis Hospital & Medical Group
- OSF St Joseph Medical Center
- OSF St Mary Medical Center
- Osmond General Hospital
- Oswego Hospital
- Othello Community Hospital
- Ottawa County Health Center
- Otto Kaiser Memorial Hospital
- Ottumwa Regional Health Center
- Ouachita County Medical Center
- OU Health - Edmond Medical Center
- OU Health - University of Oklahoma Medical Center
- Our Lady of Fatima Hospital
- Our Lady of Lourdes Heart Hospital
- Our Lady of Lourdes Regional Medical Center
- Our Lady of Lourdes Womens and Childrens Hospital
- Our Lady of the Angels Hospital