For the purposes of this paper, "vulnerable" adults include Aborigines and Torres Strait Islanders; mentally ill or mentally disordered persons; persons with developmental disabilities; persons from non-English-speaking backgrounds; and other persons who are unable to communicate well due to some type of disability. In dealing with vulnerable individuals, police must first be trained in identifying vulnerable witnesses. This paper reviews the policies for dealing with vulnerable adult suspects in the various Australian jurisdictions. There is a wide disparity in the level of detail in police policies regarding the questioning of vulnerable individuals and the extent to which such policies are available to the public. The relevant legislation in all Australian jurisdictions except the Northern Territory makes some provision for police to arrange an interpreter when the interviewee's English is limited. The legislation in New South Wales is the most extensive, as it makes special provision for a range of vulnerable persons. An overview is provided of the key issues police may encounter when questioning suspects who may be vulnerable due to their Indigenous status; cultural and linguistic diversity; and/or physical, mental, or intellectual disabilities. In evaluating police policies and practices in this area, future research should consider the practical effects of legislation and policy in police training, the management of police interviews, and the impact on criminal investigations. 42 references