In 1886 the Public Health Act established the Central Board of Health, which was responsible for the Local Boards of Health and all public health matters. It was referred to from about 1904 as the Public Health Department.

The Public Health Department and the Medical Department (which was mainly concerned with hospitals) amalgamated on 1 October 1906 under the Principal Medical Officer, Dr Lovegrove, who also became President of the Central Board of Health.

The Public Health Act of 1911 created the Department of Public Health under a Commissioner of Public Health responsible to a Minister of the Crown. The title of Principal Medical Officer was also retained. The Public Service Lists show the Department as being amalgamated until 1955. From 1956-1979 Medical and Public Health are shown as separate departments. In 1979 they were again amalgamated and on 30 April 1981 they split into the Public Health Department and the Department of Hospital and Allied Services. On 1 May 1984, the Public Health Department, the Department of Hospital and Allied Services, and the Mental Health Services amalgamated once again as the Health Department of Western Australia.