Background: The self-identification of nursing students with the profession has been linked with a successful transition, from being a student to being a professional nurse. Although there is no empirical evidence, there are suggestions that students with high professional identity are more likely to persist and complete their studies in their chosen profession. Objectives: The purpose of this study was to evaluate the psychometric properties of a professional identity scale and to determine the relationship between professional identity and student retention in a large group of first year nursing students. Design and Methods: A survey design was used to examine the professional identity of first year nursing students, as measured by the Macleod Clark Professional Identity Scale (MCPIS-9). Baseline data obtained from the initial surveys were then compared with student drop-out rates 12. months later. Results: Exploratory factor analysis of the MCPIS-9 yielded a one-component solution, accounting for 43.3% of the variance. All 9 items loaded highly on one component, ranging from 0.50 to 0.79. Cronbach's alpha coefficient of the MCPIS-9 was 0.83 and corrected item-total correlation values all scored well above the 0.3 cut-off. Students who: were females, had previous nursing-related vocational training, reported nursing as their first choice, or engaged in nursing-related paid work, had statistically significant higher professional identity scores. Using logistic regression analysis, students with high professional identity scores at baseline were more likely to be still enrolled in the nursing program at 12. months, controlling for gender, language spoken at home and engagement in nursing-related employment. These results support the psychometric properties of the MCPIS-9. Conclusions: Professional identity has a direct relationship with student retention in the nursing program. It is important to adequately measure professional identity in nursing students for the purpose of monitoring and identifying students who are at risk of leaving nursing programs. �� 2012.