This volume contains papers presented at Symposium HH 'Nanocomposites, Nanostructures and Heterostructures of Correlated Oxide Systems' held in San Francisco, California, April 9-13, 2012, during the JSAP-MRS Joint Spring Meeting (JSAP: Japan Society of Applied Physics). Future electronics will increasingly rely on oxide materials because of their unique functionalities. Advances in the synthesis and characterisation of oxide thin films and nanostructures have brought about the observation of exciting new materials phenomena. The parallel fields of oxide heteroepitaxy and nanomaterials both exploit surfaces, interfaces and boundaries in materials to achieve better performance and new properties. Core to both fields is the ability to control these structures at unprecedented atomic levels. Because of these common themes in this Symposium, researchers from both communities were brought together to identify and illuminate new areas of interaction and collaboration.