Objective: This review was conducted to investigate the impact of applying 12-hour shifts in comparison to 8-hour shifts on nurses' health wellbeing and job satisfaction. Methods: MEDLINE, CINHALE, PsycINFO, EMBASE, Web of Science, and SCOPUS databases were searched, covering the period between 1980 to 2017. Studies were included if they concerned nurses working for 12-hour shifts in comparison to 8-hour shifts in hospital settings, based on observational/surveys studies. Results: In the yielded 12 studies, 3 studies reported that 12-hour shifts had an impact on nurses' health and wellbeing, such as cognitive anxiety, musculo-skeletal disorders, sleep disturbance, and role stress; however, there was no significant difference between 12-and 8-hour shifts with digestive and cardiovascular disorders, psychological ill health, and somatic anxiety. Of the 4 studies measuring the impact of 12-hour shifts on fatigue, three studies showed that the nurses experienced more fatigue in the 12-hour shifts in comparison to 8-hour shifts; nevertheless, one study did not find a significant difference in fatigue and critical thinking performances between 12-and 8-hour shifts. Nine of the 12 studies measured job satisfaction in 12-and 8-hour shifts, 5 studies showed a greater dissatisfaction regarding 12-hour shifts, while 3 studies found that the nurses were more satisfied with 12-hour shifts than with 8-hour shifts; but one study pointed out that there was a difference between the two shifts considering pay and professional status. Conclusions: The findings of the review suggest that 12-hour shifts resulted in negative health concerns and job dissatisfaction; however, there is a need for more empirical evidence to support this.