I will review the latest LHC results of relevance for ultra-high-energy cosmic-rays physics, as well as for dark-matter searches in space and underground labs. In particular, I will review (i) the constraints that the LHC QCD data imposes on the sources and nature of cosmic rays at the highest energies measured on Earth O(10^20 eV), and (ii) the latest LHC limits on dark-matter candidates, which complement the direct (underground) and indirect (space-based) searches.