The hospital has its origins in a facility named after Richard de Wych, a former Bishop of Chichester, commissioned by West Sussex County Council in 1937 and built between 1938 and 1939.

[1] At the start of the Second World War the Government designated it an Emergency Medical Service hospital and, by 1940, ten hutted wards had been added, taking the number of beds to 594.

[1] After the hospital attained NHS Trust status in 1994, a new building, containing wards, physiotherapy and operating theatres was completed in 1996.

[3] In April 2014 the maternity unit was awarded the prestigious 'level three' award under the Clinical Negligence Scheme for Trusts[4] and in 2016 the hospital was rated as 'Outstanding' by the Care Quality Commission although they reported that the hospital's responsiveness required improvement.

The Chichester Treatment Centre treats patients on a day care basis.