This paper examines how power and knowledge are involved in the workings of speech and language therapy and in the work of speech and language therapists (SLTs). The paper draws on Foucault for its conceptual frame, with reference to his exposition of governmentality, biopolitics and pastoral power. Based on interviews with thirty-three SLTs in the UK, the findings show that evidence-based practice (EBP) is ever-present in speech and language therapy, despite its apparent absence; and that its power circulates in a multitude of ways. EBP as a process, and not an outcome, was workable. When competent practice was at risk, however, the SLTs challenged the dominance of EBP by saying it needed to 'get real' but then were troubled when it did. Working the 'wise' - those people involved with the client, including the SLTs themselves - was key to speech and language therapy; as was the making of subjects into biopolitical objects. At its most rewarding, but also most personally challenging, the work of SLTs involves mediating between different ways of being in the world and reimagining life, personhood and citizenship; to capture this complex labour process, the paper introduces the term 'pastoral labour'.