This research aims to identify the dgree of the five factors personality as well as the occupational performance of faculty members at Zagazig University, and to identify the differences according to the gender (males - females), the type of college study (scientific - literary), the secientific degree (lecturer - assistant professor - professor), and job experience (less than 10 years - From 10 years to less than 15 years - 15 years and over), on the big five personality inventory, and professional performance of faculty members at Zagazig University, and examing the relationship between the five factors of personality and professional performance. the researcher used the professional performance questionnaire (prepared by the researcher), the big five factors inventory (Costa and Makri, 1992 translated by: Ahmad Omar & Muhammad Ahmed Ali Heiba, 2011). These two measures were applied to a sample of (848) of the faculty members at Zagazig University. The finding showed The faculty members had medium degrees in three of the the five major factors of personality (neuroticism - extraversion - openness to experience), while the approval degree in two factors of (agreeableness and conscientiousness) was high. As for the professional performance, the faculty members (the research sample) in the fields of teaching, self-development, college and university service was given a high degree of approval, while the fields of scientific research and community service came with a medium degree of approval. The results also revealed a positive correlation between the five big factors of personality and the professional performance of faculty members, except for the neuroticism factor as it was negatively correlated with professional performance. No differences were found in the five big factors related to the type of college study or gender, except for the oppenness to experience, in favor of male members. There were differences in the five major factors related to the academic degree in favor of the higher academic degree. There are no differences in professional performance due to the faculty type or gender except after teaching in favor of females, while there are differences in professional performance due to the academic degree in favor of the higher academic degree, and there are differences in professional performance due to experience in favor of those with higher experience.