Introduction: Nursing practice is highly dependent on head nurses' effectiveness. And one of their most important missions is to maintain the continuing clinical competence of nurses in line with real professional needs .Development of nursing competence will be accomplished during the time when a newly graduated nurse moves towards being a professional nurse. The aim of this study is to determine changes in the clinical competence of beginner nurses in terms of Leadership Competencies of theirs Head Nurses. Methods:The present study is done via cohort method; it was conducted in educational hospitals of Mashhad University of Medical Sciences from 2014 to 2015. 37 nurse managers, 72 beginner nurses were chosen by census method and who in addition to 283 non-beginner nurses participated in this study. In order to assess the superiority of the head nurse, the Ezeukwu leadership empowerment tool was used. The qualifications of the nurses were evaluated in three stages: the beginning of the study, two and four months after the start of the study via self-assessment and peer-assessment using the Mortojja qualitative study questionnaire. The change in beginner nurses, clinical competency were evaluated in terms of their head nurses, leadership competencies. Data were analyzed using SPSS16 by Chi-Square , Fisherexact, ANOVA, Kruscal Wallise, Repeated Measure, Pearson linear correlation and relative risk calculation. Results: Average score of clinical competency of beginner nurses based on their head nurses, leadership competency in second and third evaluation stages have significant difference (P<0/05). The Relative Risk of second stages with CI=0/92-2/13, RR=1/40, P=0/141 was no significant but relative risk of third stages with CI=1/38-2/66, RR=1/92, P<0/001 was significant. Conclusion: There was significant positive relationship between leadership competency of nurses and clinical competency of beginner nurses based on their head nurses, leadership competencies.