Kings County Hospital Center is a municipal hospital located in the East Flatbush neighborhood of Brooklyn, New York City. It is owned and operated by NYC Health + Hospitals, a municipal agency that runs New York City's public hospitals. It has been affiliated with SUNY Downstate College of Medicine since Downstate's founding as Long Island College Hospital in 1860. Kings County is a member of the New York City Health and Hospitals Corporation.

Kings County was named the country's first Level 1 trauma center. It is also a Designated Stroke Center, Level III Perinatal Center, Designated AIDS Center, Parkinson's Disease Center of Excellence, Diabetes Education Center of Excellence, Behavioral Health Center (including inpatient, outpatient with dedicated emergency department) and Sexual Assault Forensic Examiner (SAFE) Program Center of Excellence.

Kings County serves the boroughs of Brooklyn and Staten Island, with over 510,000 clinic visits and 140,000 emergency department visits in 2015. The hospital provides services to more than 800,000 people in the surrounding communities, including 415,650 in the primary service area of Bedford–Stuyvesant, Brownsville, Crown Heights, Canarsie, East Flatbush, East New York, Flatbush, and Prospect Lefferts Gardens. Ethnic diversity among the mostly black and Hispanic population served (94%) by Kings County is high, with large populations from the Caribbean as well as South American and African countries. Accordingly, Kings County employees speak 39 different languages to meet this diverse population's needs.

Kings County Hospital was born of necessity, dedicated to caring for the underprivileged of Brooklyn. In 1824, New York State established a law requiring several counties, including the County of Kings (Brooklyn), to purchase lands to be used exclusively to house the poor, deferring all potential real estate taxes which could be levied on the land. The law stated that taxation of the surrounding inhabitants would be used to fund these projects.

The hospital was then established in 1830 as Brooklyn County Almshouse. The first hospital building was constructed in 1837, after land was purchased from the Martense family for three thousand dollars.

In 1857, an investigation was initiated by the temporary president of the State Senate, Mark Spencer, to visit all establishments created by the 1824 law. The investigation surveyed the Brooklyn County Almshouse, finding a hospital and lunatic asylum among other buildings constructed since the creation of the law. The hospital was a four-story 48 by 254 foot building housing 430 patients and lunatic asylum “260 feet long, wings 45 feet, and the centre 80 feet wide, four stories high” built to accommodate 150 patients but housing 205. At the height of the straitjacket, the lunatic asylum did not employ the use of physical restraints for patients, allowing them to freely mingle and take exercise at their leisure – “The resident physician observed that he considers 'kindness' more potent than chains”. The hospital and asylum each employed a single physician to care for all housed patients. Famously in 1864, Walt Whitman committed his brother to the asylum. The mid-20th century was fruitful for public health and scientific advancement at Kings County. Some of the first successful large-scale family planning services in the country were started under renowned physician Louis Hellman. It began with his fight against a ban on family planning services in New York public hospitals in 1958. In 1965, due chiefly to efforts organized by Dr. Hellman, the New York State legislature lifted the ban on the prescription of birth-control medications in public hospitals in New York State. By 1966, it was demonstrated that these efforts were highly successful in lowering abortion rates, establishing a nationwide precedent. These efforts radically changed the availability for birth control among underserved and impoverished communities.

Working with populations in which sickle cell anemia was endemic, in 1966, Drs. Margaret G. Robinson and R. Janet Watson observed a high incidence of pneumococcal meningitis in sickle cell patients – a similar rate to that of post-splenectomy patients. Upon this conclusion they developed the first explanation for such a similarity being inability of macrophage phagocytosis in these encapsulated bacteria. These results were paramount in establishing the practice of vaccinating patients with sickle-cell anemia against encapsulated bacteria.

In 1997, Kings County began a modernization program.