The study was conducted for a period of two semesters on a cohort group of pharmacy students in five courses. The main objective of the study was to assess the impact of Problem Based Learning (PBL) on the learning behavior, especially Knowledge, Skill and Attitude of the students, who entered the university after 12 years of schooling. It was a prospective study involving about 40 students of 10 nationalities with varying social, cultural, ethnic, religious and racial background. The performance within the cohort group and between the two cohort group of students and the assessment of facilitators who were faculty members with varying teaching experience, qualification and nationalities were compared. Standard, validated questionnaires were used for the assessments by students and facilitators. The data was subjected to statistical studies with t-test and chi square test to find out the significance. Bar charts were used to represent the data for easy understanding and comparison. Pre and post tests were administered in each course using Multiple Choice Questions (MCQ) and Restricted Response Essay (RRE), to assess the improvement in the overall knowledge in each course PBL in a specific content area. The study showed positive impact of PBL on the learning behavior – Knowledge, Skill and Attitude (KSA) of students. Baseline and end PBL assessment by facilitators showed improvement in student's K, S and A. Pre and post test on the PBL topics showed significant improvement in the students content knowledge.