Résumé : This study examines the contribution of perceived organisational support, job characteristics and intrinsic motivation to understanding organizational citizenship behaviour (OCB) amongst a sample of 224 nurses. We use social exchange theory to investigate why employees who received perceived organisational support develop organizational citizenship behaviours. Relatively little research has assessed whether job characteristics and intrinsic motivation predict also organizational citizenship behaviors (OCB). Yet, there appear to be natural links between job characteristics, intrinsic motivation and OCB. Consistent with our hypothesis, perceived organisational support, intrinsic motivation and autonomy were related to organizational citizenship behaviours. © 2011, Presses universitaires de Grenoble.