We explore the local negotiation of regulatory practice at the UK Stem Cell Bank, the first Bank of its type in the world. Basing our empirical work on a detailed analysis of one aspect of the Bank's regulatory commitment--the completion of the Cell Line Information form--we make visible the necessary judgements and labour involved in interpreting and operationalizing externally imposed regulation. The discussion opens by detailing the problems encountered when the Bank completes the form: reconciling a bureaucratic system of accountability with craft-like laboratory skills involving multiple kinds of tacit knowledge. We follow this by explicating the emergent 'bridging strategies' pursued by the Bank to address these issues, highlighting their reliance upon the formation of trust and social networks. The closing discussion emphasizes the contingent assembly of regulatory practices that emerge in the local setting.