Calculations of fcc aluminum matrix/Al3M equilibria for the Al-2at% (Ti, V, Zr) system have been made to predict the behavior of site fractions of transition elements in the D0(23) Al3(Ti, V, Zr) phase. It has been found out that Ti and Zr behave similarly, but V behave differently. Results show that the nominal Ti:V:Zr ratio formulated in the alloy composition is not carried through to the trialuminide phase.