Abstract: public service worldwide have been subject to externally imposed reforms utilizing tools such as financial incentives and performance targets. The adverse impact of such reform on public service ethos has been claimed, but rarely demonstrated. Individual within organizations work beyond their formal contracts of employment, described as Organizational Citizenship Behavior, to further organizational interests. Given New Public Management reform and the subsequent contextual changes in the way in which public sector organizations are managed and funded, the present study theorizes that OCB directed toward the organization may be 'crowded-out' . This article test the relationships between public service ethos and OCB and it present empirical evidence from a study in England of the ability of each dimension of this ethos to predict OCB.