Researchers have clearly indicated (Borman & Motowidlo and Organ, 1988), that in evaluations of work performance, performance on tasks directly assigned in the workstation is taken into account. But there are also other evaluations of contextual performance, referring to behaviours not directly prescribed in the job, which some people call "pro-social behaviour at work" and others, notably Organ (1988), call "organisational citizenship behaviour" (OCB). However, if these behaviors have been the subject of numerous studies in order to understand the determinants and consequences on the workers and the organization, it would be interesting to explore these OCBs in a work environment governed by a specific temporal organization, outside the conventional framework of day work. Our research will therefore attempt to shed light on the correspondence between shift work (3x8) divided into different rotations or shifts on the one hand, and the evaluation by the superior of the implementation of these non-prescribed behaviours on the other.