Construction of the hospital began in 1962 on a 74-acre plot of land on the outskirts of Smithtown, Long Island, New York. It was opened in 1962 as St. John's Smithtown Hospital, a not-for-profit hospital operated by the Church Charity Foundation of Long Island, an Episcopal (Anglican) organization. At the time of its opening, the hospital had a total of 160 employees. By its fifth year of operation, it had grown to 357 full-time employees and 151 part-time, and had provided services to nearly 100,000 patients. A local Smithtown newspaper ran an article on the fifth anniversary of St. John's opening, celebrating the hospital's delivery of Suffolk County's millionth resident. With various expansions, the hospital campus has grown to 110 acres, and now has 296 hospital beds and 240 nursing home beds. Expansions and additions to the hospital have included: • A Psychiatric Unit in 1976 • Medical Office Building in 1989 • Cardiac Care Unit in 1990 • Nursing and Rehabilitation Care Center in 1990 • Dialysis Unit in 1993 • Oncology Unit in 1994 • Endoscopy Suite in 2002 • Siena Women's Health Pavilion in 2009 • Center for Hyperbaric Medicine and Wound Healing in 2015 • St. Catherine & St. Charles Health & Wellness Center in 2017 St. John's Smithtown Hospital was purchased by the Catholic Health Services of Long Island (now known as Catholic Health) on February 29, 2000, and renamed St. Catherine of Siena Medical Center after the 14th-century Catholic saint
Catherine of Siena. == Accreditation ==