Background: Modern education in the field of healthcare is faced with the challenge of coping with one of the most important tasks - to develop in students a set of competencies which serve as a sound basis for mastering a series of job-specific knowledge, skills and abilities, and which constitute a guarantee for coping successfully with all everyday tasks. The attention of the mentor is focused on finding the most reasonable solution to the various situations that the trainee may find him/herself in, and ensuring emotional comfort., Aim: To identify the grounds and criteria for selecting mentors for the pre-graduation traineeships of the future registered nurses., Methods: To determine the opinion of the mentors, we surveyed 106 mentors in several university hospitals: 'St. Georgi' University Hospital - Plovdiv, MPHAT AD - Haskovo, 'Dr. At. Dafovski' University Hospital - Kardzhali, University Hospital - Stara Zagora., Results: During the pre-graduation traineeship in a real-life environment, students have the opportunity to develop and consolidate a series of skills, competences and qualities which are an integral part of the modern image of the registered nurse. Logically, the mentor should be the leading factor in the pre-graduation traineeship, yet the tutor has organisational and control functions., Conclusion: Mentors are expected to ensure patient safety, as well to create suitable working conditions for students., (Copyright: © 2019 Snezhana Dragusheva, Penka Petleshkova, Gordana Panova.)