Professionalism is one of the fundamental concepts in nursing and the result of the interaction with the environment and others. Nursing professionalism influences the quality of care and is affected by several factors. This study aimed to determine the attitude of nurses regarding professionalism and the factors affecting it. In this descriptive study, the attitude among nurses to professionalism has been measured through the questionnaire Hall, in five dimensions "membership in professional organizations", "public service", "a sense of calling", "self-regulation"," autonomy" and a researcher-made questionnaire about effective factors. One hundred eighty five nurses working in teaching hospitals affiliated to Tabriz University of Medical Sciences, participated in the study through stratified random sampling. The data were analyzed, using SPSS software, descriptive and inferential statistics. The results showed that the nurses' attitude to professionalism is at the average level. Among the five dimensions, the scores from the highest to lowest belonged to "membership in professional organizations", "a sense of calling", "selfregulation", "autonomy" and "public service". The relationship between nurses' attitudes toward professionalism and variables of work experience and participation in training courses for individual empowerment was found to be statistically significant. The professional attitude among nurses is at the average level. Given the importance of the professionalism in nursing and the influence of various factors, efforts are directed at achieving the desired level and reducing the barriers.