Background: Everyone expected in the workplace will behave in a professional manner, and treat each other with dignity and respect. Many times clinical nurses behaving with manager nurses inappropriately and they think inappropriate behavior is a sufficient remedy, because they often don’t realize that their actions are causing a problem. Inappropriate behavior of the clinical nurses increased turnover rates in nurse managers, also reduced job satisfaction and reducing leader abilities. Objective: The objective of the study was to measure the inappropriate behavior of the clinical nurses’ influence the nurse managers’ performance in Services hospital, Lahore. Methodology: Cross- sectional descriptive and co-relational study was conduct to measure the inappropriate behavior of the clinical nurses’ influence the nurse managers’ performance. One hundred and thirty nurse managers (n=130) were selected for that research and linear regression was used to show the correlation between the variables. Results: The results of the study showed the positive relationship between the inappropriate behavior of the clinical nurses and nurse manager’s performance. The inappropriate behavior of the clinical nurses have 30.2% (p>0.05) relationship with nurse managers performance. Conclusion: This study concludes that the inappropriate behavior of the clinical nurses influence the nurse mangers performance. The results of the study showed the with beta value .549 with (p=0.00) and R square value is 30.2%. Overall results of the study show positive relationship between the inappropriate behavior of the clinical nurses and nurse manager’s performance.