St. Mary's Good Samaritan, Incorporated (SMGSI) was created in 1996 through a unique and visionary joint operating agreement (JOA) between SSM Health Care of St. Louis (the first MBNQA winner in health care) as the managing partner, and Felician Services, Inc. (FSI) of Chicago. SMGSI is a Catholic, not-for-profit corporation pursuing a vision to create a comprehensive, regional health care enterprise covering a nine county area in South Central Illinois. This vision has been in place since 1996 and will continue into the foreseeable future.

A regional health care enterprise has and is continuing to be developed by building on the existing strengths of both St. Mary's Hospital in Centralia and Good Samaritan Regional Health Center in Mt. Vernon. These two hospitals (113 beds at Centralia and 134 beds at Mt. Vernon) anchor the continued development of tertiary services. Primary services include emergency care, medical/surgical, oncology, neurology, mental health, obstetric, cardiology, orthopedic, pediatric, and rehabilitation. SMGSI delivers its acute care services in inpatient, outpatient and emergency room settings.

Additional physician and mid-level provider services are available through SMGS Medical Group. The SMGS network is dispersed across eleven counties. Currently these outreach facilities include six community-based Family Health Centers, one outpatient psychiatry office and one physician management company encompassing nearly 50 physicians and physician extenders. Home health services are provided through SSM Home Care.

SMGSI is one of the largest health care networks operating in South Central Illinois and continues to experience growth.