  We consider the possibility that ultra-high energy cosmic rays originate from
the annihilation of relic superheavy dark-matter particles. We find that a
cross section of <sigma_A v> ~ 10^{-26}cm^2 (M_X/10^{12}GeV)^{3/2} is required
to account for the observed rate of super-GZK events if the superheavy dark
matter follows a Navarro-Frenk-White density profile. This would require
extremely large-l contributions to the annihilation cross section. We also
calculate the possible signature from annihilation in sub-galactic clumps of
dark matter and find that the signal from sub-clumps dominates and may explain
the observed flux with a much smaller cross section than if the superheavy dark
matter is smoothly distributed. Finally, we discuss the expected anisotropy in
the arrival directions of the cosmic rays, which is a characteristic signature
of this scenario.
