Research relating to Community Mental Health Teams (CMHT's) may be seen to focus predominantly upon measuring effectiveness. Studies which take a broadly social constructionist perspective of language as constitutive and purposive are relatively rare. Such research has clinical relevance since it reveals as consequential the ways in which mental health professionals represent their clients. This study examines the generation and utilisation of case definitions by participants in a single community adult mental health team allocations meeting. The conversation analytic approach adopted seeks to reveal the orderliness of the interaction, which participants can be shown orientating to as orderly with each turn of talk. The first part of the analysis shows how, in their orientation to orderliness on a turn-by-turn basis, participants co-construct this interaction as an allocations meeting. This, it is argued, produces a unique interactional context in which case definitions are generated. The second part of the analysis reveals how case definitions are generated and utilised within specific interactional contexts to accomplish situated work. The main themes arising from this analysis are discussed and include the orientated-to orderliness of the interaction, talk as context, the constructed, purposive nature of case definitions and the variability of descriptions across sequences of interaction. The clinical implications of this study are discussed and relate to the representation of clients in talk and the encouragement of reflexive practice. The implications of the Conversation Analytic perspective for Clinical Psychology research and practice, as well the notion of internal mental states are discussed. Issues pertinent to this study, such as power, social identities and use of data from a single case are critically reviewed. Finally, it is argued that there is a need for future Conversation Analytic studies which build upon the findings presented.