The Macromolecular Interactions Facility (MIF) in the Department of Biochemistry and Molecular Biology and Bio21 Institute at the Universuty of Melbourne is a collaborative platform technology resource for the biophysical characterisation of proteins and other macromolecules. It offers state-of-the-art instruments for the analysis of protein size, shape, secondary structure, interactions and complex formation, including analytical ultracentrifuges, a circular dichroism spectrometer, isothermal titration calorimeter, biolayer interferometer and fluorescence spectrometer. The analytical capabilities of these instruments extend beyond proteins themselves and have been successfully exploited for the study of drug binding, intracellular aggregation processes, nanoparticles and other systems. Our equipment is open to all academic and commercial users, and training can be provided.