Aims: To examine how the Conservation of Resources theory explains burnout in the nursing profession. Background: Burnout, which is an accumulation of work-related mental stress in people-oriented occupations, has been an issue of concern for decades for healthcare workers, especially nurses. Yet, few studies have examined a unified theory that explains the aetiology, progression and consequences of nurse burnout. Design: This discussion article integrates current knowledge on nurse burnout using Conservation of Resources theory, which focuses on four resources (i.e., objects, conditions, personal characteristics and energy). Data sources: The databases that were used in this study included CINAHL, PubMed and PsycINFO. All reviewed articles were published between January 2006 - June 2016. Findings: The Conservation of Resources theory explains that burnout will occur as a result of perceived or actual loss of these four resources. Furthermore, nurse burnout could affect work performance, leading to lower alertness and overall quality of care. Implications for nursing: Healthcare organizations and nursing administration should develop strategies to protect nurses from the threat of resource loss to decrease nurse burnout, which may improve nurse and patient safety. The Conservation of Resources theory can guide interventions to decrease burnout and future research that examines the relationship between professional nurse burnout and patient safety. Conclusion: The Conservation of Resources theory explains the aetiology, progression and consequences of nurse burnout. Future studies must explore whether nurse performance is a mediating factor between nurse burnout and patient safety.