Although several studies have shown that the problem-based learning (PBL) method promotes relevant professional skills as well as critical thinking and lifelong learning, some teachers remain sceptical regarding whether PBL is also adequate in acquiring the factual knowledge that students need. In this article, we describe an experience in which PBL has been introduced as an interdisciplinary activity in the teaching of students in the bachelor degree of biology, with special attention on the analysis of contextualised complex problems. This experience was a part of a traditional curriculum and roughly 20% of the entire learning time was devoted to it. We named this teaching approach "hybrid problem-based learning" (H-PBL) curriculum, in contrast to the lecture-based learning (LBL) traditional curriculum. The study reported here aims to answer a fundamental question: are there differences between both models in the students' factual knowledge acquisition? The results of this study have failed to show significant differences in factual knowledge acquisition between both groups of students. We conclude that the use of an interdisciplinary H-PBL approach has no deleterious effect on the recall of factual knowledge, while it may permit the simultaneous development of other professional skills, which could be more difficult to attain in traditional curricula based mainly on the lecture-based method. (Contains 1 figure and 3 tables.)