  We examine gauge and Yukawa coupling unification in models with
gauge-mediated supersymmetry breaking. We work consistently to two-loop order,
and include all weak, messenger and unification-scale threshold corrections. We
find that successful unification requires unification-scale threshold
corrections that are in conflict with the minimal SU(5) model, but are
consistent with the modified missing doublet SU(5) model for small tan beta,
and large tan beta with mu>0.

High Energy Physics - Phenomenology;High Energy Physics - Theory