Introduction and aim: Mentoring is a relationship, a process in which two or more people, the mentor, and the mentee, cooperate with the goal of growth, development, and learning. A mentor in nursing is usually a health worker who shares his knowledge and skills to the student during clinicals. It should be emphasized that mentors face certain obstacles every day, from work overload to the workplace itself, which brings with it certain specificities. The aim of this research is to gain insight into the assessment and self-assessment of mentoring during clinicals of nursing students at the undergraduate and graduate level by the mentors and nursing students themselves, and to compare the results. Methods: The research was conducted through two questionnaires that were intended for nursing students and healthcare workers/mentors. A total of 242 participants took part in the research, of which 98 were healthcare workers and mentors of clinicals and 144 nursing students from undergraduate and graduate studies. The survey questionnaires each consist of 22 questions. The questionnaires were distributed online, via social networks, in the period from May to September 2022. Results: The average score of the mentor's self-assessment of mentoring is 3,78, while the assessment of the quality of mentoring by students is an average of 3,41. Mentors/health professionals rate mentoring higher compared to nursing students. There is a statistically significant difference in the self-assessment of mentors regarding age, years of work and level of professional education. There is no statistically significant difference regarding age, way of study and work status of students. Discussion/conclusion: A mentor - a healthcare worker is a factor that enables students to learn and improve through clinical exercises. Investment in education is necessary so that every future nurse has the best and highest quality foundation for planning and implementing safe health care.