There are currently 1.3M people in Ontario experiencing both physical and mental health illness. Because the current health care system is designed to focus on either physical or mental illness, many of these patients do not receive the most appropriate treatment to address their needs which can negatively impact their health and well-being and poses an increased burden on their families. The Medical Psychiatry Alliance (MPA) was launched in 2014 to transform the delivery of mental health services for patients with combined physical and mental illness. The MPA is a first-of-its-kind $60M collaborative partnership between the Centre for Addiction and Mental Health, The Hospital for Sick Children, Trillium Health Partners and the University of Toronto. The Institute for Better Health has partnered with the MPA to support the evaluation of 4 integrated care projects, including: the Senior’s Outpatient Project for frail seniors with chronic physical health conditions and anxiety or depression; the Adult and Seniors Inpatient Project designed to prevent, recognize and treat delirium among inpatients at THP; the Child and Youth Project designed to integrate mental healthcare, both recognizing and treatment of mental health problems, in the pediatric diabetes clinic; and the Primary Care Project designed to support the collaboration of patients with Medically Unexplained Symptoms and their primary caregiver. Led by Dr. Judith Versloot (IBH Assistant Scientist) in close collaboration with Dr. Elizabeth Mansfield (IBH Scientist) and Dr. Robert Reid (Hazel McCallion Research Chair in Learning Health Systems and IBH Chief Scientist) and with a diverse team of scientists, researchers and clinicians, the project team has been successful in showing that the MPA projects at THP have improved both the mental and physical health outcomes of patients of all ages as well as the mental and physical health services at THP. Researchers at IBH continue to partner with MPA to bring cutting-edge evidence into designing the collaborative care programs and evaluating outcomes for patients, families and providers to improve physical and mental health for the community.