Background and Aim: Clinical training as the core of nursing education is a significant and essential component for developmentof professional nurses. The quality of clinical instructor's behavior plays a significant role in the learning process of the students, especially in clinical practice. The aim of the study was to assess the clinical instructor's behaviors and nursing students' perceptions toward effective clinical instructor's characteristics that facilitate learning process. Methods: Setting: The current study was conducted at Faculty of Nursing, Cairo University. Design: Descriptive, correlational design was utilized for the current study. Sample: A convenient sample of 333 was drawn from nursing students in different levels of baccalaureate nursing programs who had finished at least two clinical rotations with patient care. Tools: The Nursing Clinical Teacher Effective Inventory (NCTEI) was used for data collection. Results: Findings of the current study revealed that the highest ranked clinical instructor's behavior as reported by the student's was teaching ability category followed by evaluation and nursing competence respectively. Regarding effective clinical instructor's characteristics as perceived by students, the highest ranked one was teaching ability category followed by nursing competence and evaluation respectively. The personality and interpersonal relationship among nursing student set as the fourth and fifth factors that affect learning process in the clinical settings. Conclusions: Effective clinical instructor's characteristics that affect learning process as perceived by nursing student include matching clinical teaching abilities, nursing competence and evaluation to student understanding and experience. Also, the nursing students considered the personality and interpersonal relationship is very important characteristics to provide support and encouragement to the student during clinical practice. Recommendation: Workshops/seminars should be organized and also orientation program for all newly clinical instructors on their roles in clinical teaching. These findings may help faculty to be pleased about students' views and acknowledge the areas of success as well as areas that needs improvement.