90 Chapter 4 ABSTRACT Prison work creates ethical challenges; hence, Dutch Custodial Institutions Agency initiated a training program for prison staff to foster Moral Craftsmanship (MCS); a concept not yet defined and operationalized in literature. This study aims to 1) define MCS, 2) identify conceptual elements of MCS, and 3) develop a measurement tool for MCS. A literature and document study provided input for the definition and selection of conceptual elements. We identified three conceptual levels of MCS: individual (cognition, attitude, and actions), team, and leadership. Based on existing and newly developed items, this first MCS-Questionnaire measures the MCS of professionals. It consists of seventy items distributed across the domains: values and norms, judgment and reasoning, consultation, implementation, looking back, interactions, and leadership. We tested its usability via ‘think-aloud interviews’. This explorative study contributes to the understanding and operationalization of MCS. Validation of the MCS-Questionnaire and consensus among experts are needed for further development.