The curricular guidelines, in the health area, require professionals with general competencies in health care, decision making, communication, leadership, administration and management. The study investigated and evaluated the theoretical knowledge of undergraduate nursing students at a university Center in the state of São Paulo, in relation to mental health assistance. It was a qualitative and quantitative field research. An evaluative questionnaire was used in the sample of 75 students, belonging to four semesters (5th, 7th, 8th and 10th). It was concluded that the students of the 5th, 7th and 8th semesters have theoretical knowledge of medium level and the 10th. Semester obtained a high level of theoretical knowledge; the majority, totaling 52 (69.3%) do not want to work and would work as a last option, in mental health. Needs for changes in the dynamics of the approach of the theoretical module were pointed out and visits were proposed in mental health services, for greater contact with the people assisted in them.