Purpose: This study was conducted to determine the personality traits of nurses and the affecting factors. Material and Methods: The population of the research covered 1357 nurses working in public and university hospitals in four different cities in the Eastern Anatolia region, and the sample included 1200 nurses who could be reached and accepted to participate. Introductory Information Form and “The Big Five Inventory (BFI)” were used as data collection tools. Number, percentage, mean, standard deviation, t test, Kruskal-Wallis test and ANOVA test were used to analyse the data. This was a descriptive cross-sectional study. The mean age of the nurses in the study was 29.74±7.61 years, 50.0% of them were married, 54.8% were university graduates and 46.3% had less than 5 years of work experience in the profession. Their total mean BFI score was 3.53±0.50, and the mean scores from the subscales of extraversion, compatibility, conscientiousness, emotional instability and openness were 3.43±0.71, 3.82±0.65, 3.73±0.67, 3.10±0.60 and 3.50±0.67, respectively. Statistically significant differences were found between nurses’ age, gender, marital status, length of work experience in the profession, working hours, the place where they lived most of their lives, the education level of their mothers and fathers, birth order and the general structure of their families and the mean score from BFI subscales (p