Background: The Medical Faculty of the International Islamic University Malaysia (IIUM) runs an undergraduate medical programme which is a combination of the traditional and the newer trends of medical curriculum. The IIUM curriculum in Phase I (Years 1, 2: preclinical) is integrated organ system based, with lectures being the main method of curriculum delivery and also incorporating problem-based learning (PBL) as one of the teaching-learning approaches. Methods: The aim of this study is to examine the effectiveness of PBL teaching-learning method in IIUM in achieving the aims of the medical school as viewed by the students. A total of 287 students from Phase I and Phase II (Year 3: clinical) participated in this study at the end of academic session 2006/2007. The questionnaires distributed consisted of 33 items with four different aspects of PBL being evaluated namely; i) PBL objectives, ii) assessment of performance of the facilitators, iii) assessment of the PBL packages and iv) preferred teaching-learning approach. Results: An average of 86.4 % of students agreed that PBL sessions achieved its aims of preparing students for professional training in the clinical years. Also approximately 80% of students felt that the facilitators fulfilled their roles as PBL tutors. Students were generally satisfied with the PBL packages prepared. However about 50% of Year 2 students did not look forward to PBL sessions and only about 20% of preclinical students wanted more PBL sessions to be scheduled. This latter finding differed as 60% of the clinical (Year 3) students wanted more PBL sessions to be implemented. A significant proportion of the students also believed that they needed some prior information about the PBL case in question in order to generate lively exchange of ideas in the first sessions. Preclinical students preferred lectured-based approach as compared to PBL in contrast to the clinical (Year 3) students of whom 57% (62) preferred the PBL teaching-learning approach. Nearly 80% of the Year 3 students found the exposure to PBL sessions during their preclinical years beneficial during the clinical year. Discussion: Although our findings supported the effectiveness of PBL as one of the teaching-learning approaches (as perceived by our students) there are a few areas of concern. These include believing that a prior knowledge of the topic in question is needed to generate a lively discussion; the group not being motivated; the group members confining themselves to individual assignments only; PBL not being supportive of on-going self- assessment; the consequence of a facilitator being too dominant; and cases constructed do not reflect real clinical scenarios. Despite agreeing to its effectiveness preclinical students still preferred lecture-based approach to the PBL as they are more confident with the knowledge as obtained through the former learning modality. Conclusion: PBL is an effective learning strategy and it contributes to the teaching-learning process of IIUM undergraduate preclinical medical programme which implements a non-Problem Based Curriculum. We are of the opinion that a combination of lecture sessions and PBL best suit the IIUM medical students.