Background: Teaching and learning are fundamentally different between conventional and problem based learning (PBL) curricula. There is a transformation in the College of Medicine, Taibah University, Saudi Arabia (CMTU) from the conventional to a PBL curriculum. Aim: To compare students' approaches to learning and their perception of learning environment between conventional and PBL curricula at CMTU. Method: A cross sectional study was conducted through a self-administered questionnaire on a convenience sample from the third year undergraduate male and female medical students enrolled in both PBL and conventional curricula during the academic year 2015- 2016. Students' approaches to learning and perception of learning environment were measured using the “Approaches and Study Skills Inventory for Students (ASSIST)" and the “Dundee Ready Education Environment Measure (DREEM)" instruments, respectively. Results: A total of 101 questionnaires (49 (48.5%) and 52 (51.5%) from traditional and PBL curricula, respectively) were analyzed. When compared to conventional curriculum students, PBL curriculum students showed a significantly higher overall DREEM (136.98 ±21.45 vs. 111.59 ±27.93; p <0.001) as well as all its subscales. Significantly higher ratings for strategic approach towards learning (60.77 ±9.12 vs. 56.35 ±9.93; p=0.02) and net learning orientation (deep approach + strategic approach - surface apathetic approach; 85.60 ±17.32 vs. 77.76 ±20.63; p=0.04) were seen in PBL curriculum students. Conclusion: The transformation to a PBL curriculum at CMTU was accompanied by a tilt in the learning style towards a desired deep and strategic learning styles and a definite improvement in the perception of learning environment among students.