114 Chapter 5 ABSTRACT This study explores the impact of participation in a series of Moral Case Deliberation (MCD) on the moral craftsmanship (MCS) of Dutch prison staff. Between 2017-2020, ten MCD sessions per team were implemented in three prisons (i.e., intervention group). In three other prisons (i.e., control group) no MCD sessions were implemented. We compared the intervention and control group using a self-developed questionnaire, administered before (pre-measurement) and after the series of MCD (post-measurement). After the series of MCD, participants scored significantly higher on 7 of the 70 items related to MCS. On some items there were significant impact differences between the various professional disciplines. Possible explanations for a relatively low impact are discussed. A shorter and validated questionnaire is needed in order to further study the MCS of professionals and the impact of Ethics Support Services. Overall did this study show that there was a positive development on some elements of MCS after participation in a series of MCD sessions.