Purpose: The purpose of this study was to identify non-psychiatric nurses’ difficulties in caring for patients with mental illness. Methods: Datawere collected from eighteen general medical-surgical nurses working at a university hospital in Seoul, Korea. This study involved two focusgroup discussions and three in-depth individual interviews. All interviews were recorded and transcribed as they were spoken, and data were analyzedusing qualitative content analysis. Results: General medical-surgical nurses experienced difficulties in 3 categories, 9 subcategories, 27codes. The three categories were ‘nurse’ related factors, ‘patient’ related factors, ‘resource’ related factors. The nine categories were ‘unpreparedness’,‘nursing barriers due to stigma’, ‘undervaluing and avoidance of psychiatric nursing’, ‘eroding into the trap of a vicious cycle’, ‘facingunapproachable patients’, ‘dealing with unhelpful family members’, ‘burdening already overburdened staff’, ‘obstructive environment’, and ‘isolationof staff with heavy responsibilities’. Conclusion: The results of this study indicate the need to develop psychiatric mental health educationprograms for non-psychiatric nurses. Education about psychiatric mental health and support from institutions for non-psychiatric nurses can reducetheir negative attitude toward psychiatric patients and difficulties in caring for psychiatric patients.