Background: Assertiveness is a communication style, which is the key to successful relationships with clients, the family, the nurses, and colleagues. Assertiveness is a key attribute for nurses without which true autonomy, professional status or empowerment cannot be achieved. Nursing involves fulfilling several roles, including interacting with clients, peers, and other health professionals. The current study aimed to assess the effect of assertiveness behavior on nursing professional behaviors among nursing staff. Research design: A descriptive correlational research design was used to achieve the aim of the current Study. Setting: The study was conducted in the critical areas at Health Insurance Hospital in Minia city, Egypt.  Sample all nursing staff who working in critical areas at health insurance hospital during the period of data collection. Their total numbers were 85 nurses.
Data Collection Tools. Tool (I): It was included two parts: Part 1: Personal data. Part 2: Assertiveness behavior questionnaire. Tool (II): Nursing professional behaviors observational sheet. Results: Most of the studied sample had high level in assertiveness behaviors and total nursing professional behaviors and, there are strong correlation between total nursing professional behaviors of the studied nursing staff and their nursing professional behaviors and communication skills, conflict, self-conflict factors and total assertiveness behaviors. Conclusion: Strong correlation between assertiveness behavior of nursing staff and their nursing professional behaviors and communication skills. Recommendations: conduct assertiveness training program is recommended for all nurses to improve and enhance their self-esteem and assertiveness and maintain periodical meetings for nurses from different hospitals by seeking their opinions and exchanging their experiences during the different situations.