Kejal Kantarci, MD from the Mayo Clinic, Rochester, MN summarises a session she chaired on the pathologic heterogeneity of Alheimer’s disease (AD) at the Alzheimer’s Association International Conference (AAIC) 2017, London, UK. During the session, 4 interesting presentations were made. The first explained how only 25% of AD patients have pure AD. The rest are due to mixed pathologies. The remainder of presentations provided supporting evidence on heterogeneity and mixed pathologies by showing how there are differences in pathology in early and late onset AD patients, and differences in clinical features in variants of AD. Furthermore, imaging also appeared to support heterogeneity by showing the different features of mixed pathologies.