Even though opinions differ as to whether lecturing is compatible with problem-based learning (PBL) or not, lectures are still a common form of instruction in PBL curricula. This paper discusses the lecture in the framework of theories of learning in general and the medical problem-based learning tradition in particular. An example of how theories of learning can be implemented in the lecture hall is presented. Theories that underpin PBL as an educational philosophy rather than as a method of instruction are reviewed. A lecture form, organized in introductory, in depth and application lectures, that responds to important factors for stimulating deep processing of knowledge and meaningful learning is discussed. Examples of and practical points about how to renew and restructure lectures in a way that counteracts surface approaches to learning, teacher centering and student passivity are presented. We argue that, with proper awareness of possible drawbacks of the large format, lectures can be used as valuable tools for learning also in a PBL curriculum.