Background: Toxic leadership is ineffective conduct that embodies the bad or dark side of leadership and can negatively affect not only the followers but also the whole organization. Aim: Investigate the relationship between toxic leadership and staff nurse's deviant behaviors at Itay El Baroud General Hospital. Design: A descriptive, correlational research design was used to conduct this study. Setting: The study was carried out in all inpatient units (medical and surgical) and Intensive Care Units (ICUs) (n=16), namely: (1) medical units (n=8), namely: general medical (Male and Female), obstetric, pediatric, poison, orthopedic, neurosurgical, and dialysis units; (2) Surgical units (n=4), as follows: general surgical (Male and Female), and operation units; (3) ICUs (n=5), as: general, neonatal, pediatric, coronary care, and emergency unit at Itay El Baroud General Hospital. Subjects: Two groups of subjects were included; (a) All head nurses and their assistants (n=32), (b) All staff nurses (n=300). Tools: Two tools were used for data collection; toxic leadership scale and deviant workplace behaviors scale. Results: There was no statistical significant difference between head nurses and staff nurses regarding total toxic leadership and it's all dimensions and less than half of studied subjects, got moderate mean percent scores of total toxic leadership. There was statistical significant difference between head nurses and staff nurses regarding organizational deviance and above one third of studied subjects, got moderate mean percent scores of total deviant workplace behaviors. Conclusion: Highly positive statistical significant correlations between total toxic leadership and its dimensions and between total workplace deviant behaviors and its dimensions. Recommendations: The study recommended establishing leadership training programs to provide health care supervisors with the skills they need to build a collaborative and participatory management organization, thus reducing deviant workplace behaviors of staff nurses.