Background: Pharmacological knowledge learning is of great importance to nursing students. The views of nursing graduates in this regard are acknowledged because this will lead to identifying the strengths and weaknesses of educational programs, resources, and trainers. Objectives: Therefore, the aim of this study was to investigate the factors affecting pharmaceutical care learning in clinical education from the viewpoint of nursing students in 2016-2017. Methods: A descriptive cross-sectional study was conducted on nursing students (n = 120) recruited through a census method. The data collection tool was a self-administered questionnaire consisting of two parts. The first part was to gather demographic information including age, sex, semester, history of student work, and written score of the pharmacology course, and the second part was related to the areas affecting the learning process including professional competence of the instructor (11 items), teaching ability of the instructor (13 items), interpersonal communications of the instructor (5 items), clinical teaching environment (11 items), course plan (3 items), and learner characteristics (8 items). The collected data from 100 students were analyzed by SPSS16 software using descriptive statistics. Results: 47 (47%) male students participated in the study and most of the participants (59%) were aged 20-21 years. From the viewpoint of the students, the variables related to the areas of the clinical instructor, learner characteristics, and educational environment were the first to third factors affecting the pharmacological care learning, in sequence. Conclusions: Paying attention to the characteristics of the instructor, adaptation of clinical environment, characteristics and motivators of the students in gaining experience, and understanding the importance and necessity of learning the knowledge and practice of medicines can facilitate and strengthen the pharmaceutical care learning.