Background: Effective leadership is essential to passing through obstacles facing the health field. The current health care system in Iran has major problems and gaps in the field of effective leadership. The aim of this study was to evaluate hospital managers' leadership style through self-assessment and to determine the correlation between leadership styles with healthcare executives' leadership readiness and leadership effectiveness. Methods: In this cross-sectional study a self-administered questionnaire completed by all internal healthcare executives of all teaching and non-teaching hospitals affiliated to Iran University of Medical Sciences. Questionnaire was composed to determine demographic information, leadership style questions, leadership effectiveness and leadership readiness. Descriptive statistics and Pearson correlation coefficient were used for data analysis. Results: According to the findings, the dominant style of healthcare executives was transformational leadership style (with a score of 4.34). The leadership effectiveness was estimated at about 4.36 that shows the appropriate level of leadership effectiveness. There was a significant correlation (correlation coefficient of 0.244) between leadership readiness and transformational leadership style (p<0.05). Also, there was a significant correlation between leadership effectiveness with transformational (0.051) and transactional (0.216) styles. Conclusion: There was a correlation between leadership readiness and leadership effectiveness with leadership styles. Application of this research will be crucial to universities and healthcare executives. This study suggests that strengthening the scientific basis is essential for leadership readiness and leadership effectiveness in healthcare system