The advent of HIV/AIDS has presented a major ideological challenge to established drug treatment agencies, where the incorporation of HIV-prevention strategies has proved problematic. This case study analyses the response to the HIV/AIDS epidemic by the drug misuse services of one Inner London district health authority (Bloomsbury) during the period 1985-89. While innovation and enthusiasm were much in evidence, a number of special problems prevented an effective and coherent strategic response. Key factors in the management of change in drugs/HIV services are identified which may be of special importance to clinicians, managers and funders and a number of key organizational and managerial competencies are suggested.