Aims: To investigate how job demands and resources interact with each other to predict intention to leave among assistant nurses and Registered Nurses. Design: Longitudinal study. Methods: Questionnaire data were collected yearly during three years (October 2012–December 2014) from Registered Nurses (RN) and assistant nurses (N = 840) employed in Swedish hospitals. Associations and interaction effects of demands and resources were assessed with correlation analyses and regression models. Results: Job demands predicted assistant nurses' intentions to leave, while resources predicted RNs' intention to leave. For RNs, several resources were functional in moderating the associations between demands and intention to leave: social support, vertical trust, and humanity moderated work pace and workflow moderated emotional demands. For assistant nurses, organizational clarity and interprofessional collaboration moderated emotional demands. None of the resources had a moderating effect on the associations between quantitative demands or illegitimate tasks and intention to leave.