Objectives: The aim of this study is to examine the metaphors nursing students use for the concept of "Mental Illness"to identify their perceptions on this subject.Methods: The research was carried using a phenomenological design, a qualitative research technique. The studygroup of the research included a total of 496 nursing students studying at Ankara University Faculty of Health Sci ences Nursing Department in the 2017-2018 academic year. A form titled, "Metaphorical Perceptions Data CollectionForm", which was prepared by the researchers in line with the literature, was used for data collection. On this form,every participating student was asked to fill in the gaps in the following sentence: "Mental illness is like..................... be cause..................... ". Analysis of data consisted of 5 steps: S1) identification of metaphors, (2) classification of metaphors,(3) category development, (4) validation and reliability and (5) data transfer to SPSS package program for quantitativedata analysis.Results: The students produced a total of 353 valid metaphors for the concept of mental illness. The metaphors ob tained were examined in terms of their common characteristics and collected under seven conceptual categories,namely, mental illness as “desperation”, “an uncontrollable condition”, “a need for care, attention, and support”, “uncer tainty”, “a damaging element”, “an impact-response”, and “an element requiring effort”.Conclusion: The results revealed that the students' mental illness-related metaphors were largely negative. In the lightof these results, it can be recommended that vocational education focuses on transforming the negative perceptionsstudents have on mental illness into more positive images. To achieve this, it is suggested that the number of coursehours on this subject be increased and that practical activities related to this subject be organized.