Background: The importance of readiness to change among first line nurse managers of organization has been recognized as a critical factor in the success of organizational change efforts. These changes within the health care are very important for improving nurse managers' work effectiveness and efficiency. Purpose: This study was carried out to explore the relationship between work effectiveness and readiness to change among first line nurse managers. Design: A descriptive correlational research design was utilized for this study. Setting: Conducted from different departments at Menoufia University Hospital, Teaching Hospital and El Helal Hospital at Shebin-ELkom. Sampling: A Convenience sample of 181 first line nurse managers was included at this study. Instruments: Two instruments were used for data collection. Instrument one: work effectiveness questionnaire (WEQ). Instrument Two: Readiness to change scale. Results: Revealed that the majority of studied first line nurse managers had high level of work effectiveness (94.7%)  , and also the majority of studied nurse managers had a high level of readiness to change (91.4%). Conclusion: There was a highly statistical significant positive correlation between level of work effectiveness and readiness to change. Recommendation: Strategies and policies should be developed to improve work effectiveness and readiness to change among first line nurse managers.