BACKGROUND: Clinical experience associated with the fear and anxiety of nursing students in the psychiatric unit. Mental health nursing instructors find it challenging to teach nursing students to deal with patients with mental disorders in an environment where they need to provide patient teaching and clinical decision-making based on evidence and new technology. OBJECTIVE: To measure the effectiveness of clinical teaching of mental health courses in nursing using clinical supervision and Kirkpatrick's model evaluation in the psychiatry unit of Imam Reza Hospital, Bojnurd, Iran. METHODS: This cross-sectional study was carried out from 2011 to 2016 on 76 nursing students from a university as part of a clinical mental health course in two semesters. The students were selected by a non-probable convenient sampling method. After completing their clinical education, each student responded to checklist questions based on the four-level Kirkpatrick's model evaluation and open questions relating to clinical supervision. Finally, all data was analyzed using the SPSS version 16. RESULTS: The students have evaluated clinical supervision as a useful approach, and appreciated the instructor's supportive behavior during teaching and imparting clinical skills. This has made them feel relaxed at the end of the clinical teaching course. In addition, in the evaluation through Kirkpatrick's model, more than 70% of the students have been satisfied with the method of conducting the teaching and average score of nursing students' attitude toward mental health students: Their mean self-confidence score was 18.33±1.69, and the mean score of their performance in the study was evaluated to be 93.74±5.3 from 100 points. CONCLUSION: The results of clinical mental health teaching through clinical supervision and Kirkpatrick's model evaluation show that the satisfaction, self-esteem, attitude, and skill of nursing students are excellent, thereby portraying the effectiveness of clinical teaching. But this program still needs to be reformed. To establish long-term goals and obtain knowledge and clinical skills of nursing, it is recommended to develop a curriculum and evaluate it appropriately.