Key Words: marginalised groups, hidden populations, sampling methods, qualitative methods Marginalised groups in Australia are known to be underserved and hard to reach and present a major challenge in Public Health. Identifying appropriate and sensitive ways to access such groups is essential if their health and health related needs are to be identified and relevant and effective health promotion messages developed.Traditionally Public Health research has used sampling methods which are effective in accessing 'easy to reach' groups such as service users and those accessed through population-based surveys. However, researchers concerned with marginalised groups and sensitive health issues have sought to develop alternative methods, often drawing on those used in other disciplines and recognised as successful in accessing members of hard to reach groups. These alternative or innovative approaches involve active outreach to seek information from members of hard to reach groups about their experiences and views. A key feature of this approach is that it has been applied with intent to see the participants benefit from the study. This active participatory method is underpinned by Primary Health Care principles and is also the basis of action research.