The Scottish Health Informatics Programme (SHIP) was a Scotland-wide research programme exploring ways of collecting, managing and analysing electronic patient records for health research. As part of the SHIP public engagement work stream, a series of eight focus groups and a stakeholder workshop were conducted to explore perceptions of the role, relevance and functions of trust (or trustworthiness) in relation to research practices. The findings demonstrate that the public's relationships of trust and/or mistrust in science and research are not straightforward. This paper aims to move beyond simple descriptions of whether publics trust researchers, or in whom members of the public place their trust, and to explore more fully the bases of public trust/mistrust in science, what trust implies and equally what it means for research/researchers to be trustworthy. This has important implications for public engagement in interdisciplinary projects.