Since 2007, Center of Excellence for High Performance Materials - University of Tehran, has arranged a series of bi-annual conferences focused on Ultrafine Grained and Nano-Structured Materials. The purpose of these meetings is to allow those interested in the field to get together to present their research in a setting that fosters discussion, collaboration, and advancement in the field. Most of the papers presented in previous meetings were of high quality scientific standards and published in the International Journal of Modern Physics-B. The 3rd conference is organized jointly by University of Tehran, Iran and University of Patras, Greece. Selected papers presented in this conference will be peer reviewed and published in a reputable journal.