Introduction: Mentoring is an important strategy to support the development of a transformational leader. It involves the nurturing of a personal career, intellectual growth/development, as well as improving corporate knowledge, and making employees feel valued. Aim: This study aims at exploring the knowledge and opinions of nurse leaders on clinical mentoring using pre-test and post-test evaluations. Methods: It is a pre-test and post-test single-subject design among 135 Chief Nursing Officers (CNO) that attended the Nurse Leaders’ Summit. Data were analyzed using SPSS 22.0, and probability value p<0.05 was used to determine the significance of the descriptive and inferential statistics. Results: The study revealed that 56.3% of the respondents had adequate knowledge of mentoring at pre-, and 74.1% at post-evaluation; 91.1% claimed to be mentors; 57% were not assigned to a mentee; while 64.4% of them had a good opinion of mentorship and were willing to practice clinically based mentoring. Conclusions: Mentoring is an effective intervention to build the capacity of nurses and improve the quality of healthcare delivery.