Background: Leaders play a crucial role in employees' lives by providing guidance and accomplishing their priorities and targets. The more real the leaders are, the more psychological contract breaches the employees will have, which will make them more likely to stay with the entity. The aim of the study is to explore the relationship between authentic leadership, psychological contract breaches, and organizational cynicism. In addition, we are testing a new mediation model of authentic leadership between psychological contract breaches and organizational cynicism among staff nurses. Research design: A descriptive correlation design was used. Sample: A convenience sample of 132 staff nurses was chosen from El-Fayoum University hospitals. Tools for data collection The Authentic Leadership Scale, Psychological contract breach scale, and The Organizational Cynicism Scale. Results: authentic leadership was significantly and positively correlated to psychological contract breach (r = 0.449, P = <.001). However, authentic leadership was significantly and negatively correlated to organizational cynicism (r = - 0.328, P =<0.001) and r = 0.431, P = 0.000, respectively). In addition, there was a significant and negative correlation between organizational cynicism and psychological contract breach. Conclusion: authentic leadership are effective in improving nurses' psychological contract breaches and organizational cynicism. As well, authentic leadership fully mediated the relationship between psychological contract breach and organizational cynicism. Recommendation: Implement leadership-training programs to develop authentic leadership skills among nurse leaders. As well, manage psychological contracts breach by ensuring clarity, fairness, and consistent fulfillment.