RICAP'11 is the third edition of the RICAP Conference. The acronym stands for Roma International Conference on Astro-Particle physics, the Conference is entirely dedicated to high energy cosmic rays study and it is organized by the three public Universities of Roma (University “Roma Tre”, University “La Sapienza” and University “Tor Vergata”). These Institutions provide both theoretical and experimental contributions, and participate to major experimental projects in the field (AGILE, AMS, ANTARES, ARGO, Auger, Fermi, KM3NeT, NEMO, PAMELA, ...). The Conference is held every two years. The first edition was held at the University “La Sapienza”, the second edition was hosted by University “Tor Vergata”.