  Axion/axino dark matter (DM) is explored in the minimal supergravity (mSUGRA)
and Yukawa-unified supersymmetric grand-unified theory (SUSY GUT) models with
surprising results. For this type of scenario, relic DM abundance has three
components: {\it i}.) cold axions, {\it ii.}) warm axinos from neutralino
decay, and {\it iii.}) cold or warm thermally produced axinos. Reheat
temperatures $T_R$ exceeding $10^6$ GeV are required in order to solve the
gravitino/Big Bang Nucleosynthesis (BBN) problem while also allowing for
baryogensis via non-thermal leptogenesis. In order to attain high enough reheat
temperatures, we also need high values of the Peccei-Quinn (PQ) breaking scale
$f_a$ on the order $10^{11}$-$10^{12}$ GeV.
