Background: Toxic leadership is a combination of self-centered attitudes and behaviors that negatively affect employees and lead them to engage in counterproductive work behaviors which also affect patients' outcomes. Aim: This study aimed to exploring the relation between Toxic Leadership and Counterproductive Work Behavior among Nursing Personnel. Setting: The study was conducted at all available department at Badr university hospital which is affiliated to Helwan university hospitals. Research design: A descriptive, correlational design was used. Subjects: The subjects of this study included all nursing personnel who are working at the time of data collection. The study sample was (n=107) of nursing personnel. Data collection tools: The data were collected by using two tools namely; Toxic leadership scale and Counterproductive Work Behavior Questionnaire. Results: The study revealed that total high mean score of toxic leadership was 66.26±21.3 as perceived by the studied nursing personnel while; total high mean score of counterproductive work behavior was 86.49±20.4 among the studied nursing personnel. Conclusion: There was a highly strong statistically significant positive correlation between toxic leadership and counterproductive work behavior among the studied nursing personnel. Recommendations: establish clear policies regarding acceptable behavior and workplace standards. Inspiration ethical leadership within the organization. Leaders should demonstrate integrity, fairness, and professionalism, and positively affected on nursing personnel.