Purposes: Attitudes toward mental illness and patients with mental illness influence the treatment they receive and decisions of policy makers. The purposes of this study were to assess Jordanian nursing students' attitudes towards mental illness, and to assess the effectiveness of teaching and contact on changing nursing students' attitudes about mental illness. Methods: A quasi-experimental, one group pretest-posttest design was employed to test the hypotheses. Opinion about Mental Illness (OMI) Questionnaire which was composed of five subscales was used to test the research hypotheses. The sample consisted of 193 Jordanian nursing students studying at the Hashemite University. Results: Results showed that (1) nursing students were found to have positive attitudes towards mental illness in four scales, (2) no significant differences were found between students' attitudes towards mental illness and demographics, (3) there was a significant difference in attitudes towards the mental illness between students who had previous contact with mental patients and those who did not, and (4) students' attitudes towards mental illness were changed positively in all scales after taking the course. Conclusions: Attitudes about mental illness will positively change if we correct some myths about it by increasing students' knowledge and by giving them the opportunity to contact those groups of patients. (Contains 3 tables.)