Evidence of large numbers of people who are both homeless and drug dependent, the complexity of their needs, and the many difficulties which they can encounter when trying to access assistance highlight the importance of basic standards of good practice in working with homeless drug users. This is particularly relevant given the growth of new managerialism and the expansion of social care markets occurring within the UK public sector since the 1980s. Within this context, the aim of the present paper is to further understanding of how best to provide support to homeless drug users by examining good practice from the perspectives of both service providers and service users. Data were collected from 48 semi-structured interviews (12 with staff and 36 with clients) conducted in six case study agencies (three homelessness agencies and three drug agencies). Interviews were audio-recorded and the data were analysed using Framework. Findings from the study revealed that good practice related to five broad areas. These were: (1) staffing; (2) agency environment; (3) support provided; (4) service delivery; and (5) agency aims and objectives. Similarities between the views of service providers and users were evident. However, differences of opinion suggested that the best definitions of good practice are achieved by consultation with a range of stakeholders (including staff and clients). Data also showed that good practice is fundamentally related to the qualitative and intangible aspects of service provision, and not just to more easily quantifiable inputs, processes, outputs and outcomes. The paper concludes by arguing that the challenge for new managerialism is to build evaluation frameworks which can accommodate this complexity, and thus, begin to portray good practice in a more accurate and meaningful light.