  The axino is the fermionic superpartner of the axion. Assuming the axino is
the lightest supersymmetric particle and stable due to R-parity conservation,
we compute the relic axino density from thermal reactions in the early
Universe. From the comparison with the WMAP results, we find that thermally
produced axinos could provide the dominant part of cold dark matter, for
example, for an axino mass of 100 keV and a reheating temperature of 10^6 GeV.
