Established in 2019,[2] it is a mass membership organisation of "renters, council tenants, mortgage holders and people in emergency & precarious living situations".

[4] CATU members are organised in local branches across the island of Ireland,[5] with committees elected by local members.

A national committee coordinates the work of local branches.

[1] CATU organises campaigns at local and national level, and its work is grounded in principles of direct action.

[6][7] Modelled after other ACORN International affiliated tenants' unions such as Scottish Living Rent, CATU was influenced by the work of the National Association of Tenants Organisations (NATO),[8] which represented tenants in Ireland in the sixties and the seventies, famously leading a national rent strike from 1970 to 1973.