Background: The emphasis placed on ethics and moral considerations has always been considered in individual and social domains, and moral intelligence is one of the important components that can play a key role in the improvement of nursing profession. In fact, among different professions, nursing is a clear indication of moral performance. Objectives: The overriding aim of the present study was to evaluate the moral intelligence of nurses working in hospitals of Guilan Province, Iran. Methods: This cross-sectional descriptive study was conducted among 200 nurses working in hospitals of Guilan Province. The participants were chosen using the two-stage cluster sampling method. Data were collected using Lennick and Kiel's moral intelligence scale, which is a standard and localized questionnaire. To analyze the data, Mann-Whitney and Kruskal Wallis tests were run in SPSS, version 16. Results: The highest percentage of the respondents (65%) had a moderate level of moral intelligence, and the least percentage of the subjects (4.5%) had a low level of moral intelligence. Three moral competencies including "Admitting mistakes and failures" (15.46 ± 0.093), "Keeping promises" (15.24 ± 2.13) and "Actively caring about others" (15.16 ± 2.32) achieved the maximum scores within the range of 4 to 20. Were the most important competencies of moral intelligence, respectively. The Kruskal Wallis test reflected a significant difference in the comparative study of nurses' moral intelligence based on age, gender, department, and educational level (P < 0.05). Conclusions: The desirable level of moral intelligence in nurses indicates the importance of obtaining moral values and emphasizes the existence of moral values in the clinical environment. Attention to factors affecting moral intelligence plays an important role in improving nurse's clinical performance.