Learning in the clinical environment is an essential part of nursing education programs. Effective clinical teachingis crucial for the learning of nursing students in the clinical settings. It helps in preparing students for the work they will have to do as practicing nurses [1]. The study aimed to identify the undergraduate nursing students' and clinical instructors' perceptions of the characteristics of an effective clinical instructor at the Faculty of Nursing-Cairo University. A descriptive cross-sectional design was utilized of the study. This study was conducted at the Faculty of Nursing, Cairo University. A convenience sample of (591) nursing students and (112) clinical instructors who are working at the Faculty of Nursing-Cairo University and are willing to participate in the study. The Nursing Clinical Teacher Effective Inventory (NCTEI) was used for data collection. Results indicated that the categories of teaching ability and interpersonal relationships were the most valued characteristics rated by both undergraduate nursing students and clinical instructors. While, the least valued characteristics rated by both undergraduate nursing students and clinical instructors were the categories of nursing competence, personality traits and evaluation. The study recommended that workshops/seminars should be organized to orient clinical teachers on their roles in clinical setting. Periodic clinical instructors' evaluation is necessary to incorporate unused behaviors, into their practice.