Introduction: Pain is not simply a consequence of damaged tissue, but rather a much more complex process that includes biological, psychological and social factors. Pain assessment is crucial to the medical treatment of children in pain. The nurse plays an important role in assessing pain levels of a preschoolers, a skill which requires a lot of knowledge and experience. Purpose: By systematically analysing the available literature we have presented the concept of pain and some pain measurement scales, while focusing on the role of the nurse in the medical assesment of preschool children's pain. With the help of electronic polls we investigated how much knowledge the students at the Faculty of Health Sciences (Nursing Department) at the University of Ljubljana have on the subject of recognizing and assesing the pain of preschoolers. Methods: This thesis is based on the quantitative approach to research. We collected data using a structured survey questionnaire. The sample included 104 full-time and part-time students of the 1st, 2nd, and 3rd year at the Faculty of Health Sciences (Nursing Department) at the University of Ljubljana. We analysed the acquired data and used basic descriptive statistics to process them, and illustrated them in the form of tables and graphs. Results: The results showed that students generally have low levels of knowledge about prechool children pain assessment and also lack knowledge in the area of general pain assessment. The level of knowledge about assessing pain of prechool children did increase along with the year the students were currently studying in, but the majority of them expressed a desire to acquire additional knowledge. Discussion and conclusion: Our research confrmed our set hyphotheses, all of which indicated the necessity for a supplementation of the undergraduate nursing course. We find that additional research, expanded across all institutions in Slovenia that provide students with a course in nursing, would enable a more in-depth analysis of knowledge possesed by the students and the ability to critically compare these findings.