  Two of the greatest mysteries of modern physics are the origin of the dark
matter in the universe and the nature of the highest energy particles in the
cosmic ray spectrum. We discuss here possible direct and indirect connections
between these two problems, with particular attention to two cases: in the
first we study the local clustering of possible sources of ultra-high energy
cosmic rays (UHECRs) driven by the local dark matter overdensity. In the second
case we study the possibility that UHECRs are directly generated by the decay
of weakly unstable super heavy dark matter.
