The two threads which run throughout the history of 204 (North Irish) Field Hospital are those of pride in the medical professionalism with which the soldier is cared for and courage and fortitude in applying that professionalism in arduous conditions.
 
On 8th May 1961, 4 General Hospital (Territorial Army) was formed as an independent medical unit of the Territorial Army.
 
By 1962, following an extensive recruitment campaign, it was a well recruited and experienced unit with several of its personnel having seen War Service between 1938 and 1945.
 
After a period of re-organisation, 204 (North Irish) General Hospital Royal Army Medical Corps (Volunteers) was formed as a successor to 4 General Hospital.
 
During the 1970's, recruitment became very difficult due to the security restrictions caused by the troubles within Province. Having the Headquarters based on the Antrim Road at this time was less than ideal.
 
In the 1990's, after yet another re-organisation, 204 became a 200 bedded Field Hospital.

On the 28th June 1998 204 (North Irish) Field Hospital (Volunteers) were granted the Freedom of the Borough of Castlereagh for devotion to duty and service to Castlereagh and Northern Ireland for the previous 100 years.
 
Headquarters 2 Medical Brigade was formed and became operational on 1st April 2001 when it assumed Operational Command responsibility for the ten Army Medical Services Independent Field Hospitals.
 
Since the onset of the Gulf War in 1991, 204 (North Irish) Field Hospital has continually had personnel on Operations in support of the Regular Army to places such as Bosnia, Kosovo, Sierra Leone, Cyprus and recently in support of recent operations in the Gulf region.