The functions of the Department of Agriculture included: establishment of experimental stations throughout the colony; making analyses of typical soils; disseminating meteorological information; improving the dairying and livestock industries; preventing the adulteration of chemical manures; introducing and distributing new varieties of fodder plants, cereals and fruit trees; excluding or eradicating insect pests and introducing new and improved mechanical appliances for use in agricultural pursuits.

The Department of Agriculture had a broad role to foster the State's agriculture and the overseas marketing of its products by representation on the Australian Agricultural Council, it helped establish nationally acceptable policies. It was the branch of the State Government service which brought scientific advice to farmers and pastoralists, conducting a wide range of research and administering relevant Acts of Parliament. It maintained services to assist farmers and its regulatory work consisted of carrying out the provisions of some laws relating to Agriculture.

The Department of Agriculture became the Department of Agriculture and Food WA (DAFWA) in March 2006 to reflect the department's increased focus on food and trade development, food marketing, food integrity and regional food development.