Background, toxic leadership becomes a common reality in many organizations. It can cause harm not only to the followers but to the whole organization, results in adverse negative consequences such as decreased motivation, productivity and cooperation which consequently effect on their emotional intelligence and organizational citizenship behaviors. Aim of this study was to determine effects of toxic leadership on intensive care units staff nurses' emotional intelligence and their organizational citizenship behaviors at Tanta International Teaching Hospital and El-Menshawy General Hospital. Subjects and Method, descriptive, comparative study design was adopted. All intensive care units at Tanta International Teaching Hospital and El-Menshawy General Hospital were included. All available staff nurses (n=486) at Tanta International Teaching Hospital ICUs (n=253) and ElMenshawy General Hospital ICUs (n=233) was included in this study. Three tools for data collection were used, Toxic Leadership Scale, Emotional Intelligence Questionnaire and Organizational Citizenship Behavior Questionnaire. Results of the conducted study revealed that toxic leadership perceptions of the staff nurses had statistically significant differences in each of four dimensions at two hospitals. At Tanta International Teaching Hospital the majority of staff nurses perceived that their leaders had low overall toxic leadership level compared to high percent had moderate overall toxic leadership at El-Menshawy General Hospital. There was a moderate level of overall emotional intelligence and organizational citizenship behavior at Tanta International Teaching Hospital, compared to low level at ElMenshawy General Hospital.Conclusion,there was a statistically significant negative correlation between total staff nurses' perceived toxic leadership with their emotional intelligence and organizational citizenship behavior at both hospitals. Therefore, it was recommended that, the health care organizations should focus on staff nurses feedback regarding their supervisors which will help in identifying supervisors with toxic traits also, need to enhance nursing staff leadership, emotional intelligence and organizational citizenship skills through periodical educational programs.