The Nobel Workshop ‘Fundamentals of Biomolecular Function: Nucleic Acids, Proteins, and Membranes’, was hosted by the city of Coimbra, Portugal, and the University of Coimbra in May 2005. The workshop focused on three subjects: (i) the functions of biological macromolecules, (ii) the interactions underlying these functions, and (iii) new techniques for studying these interactions. A brief summary of the discussions follows.