We present studies on both the electronic and magnetic properties of LaCo13 and La(FexAl1-x)13 intermetallic compounds by cluster model calculations within the scheme of density‐functional theory. The equilibrium structures of the isolated and embedded clusters, obtained by minimizing the total binding energy, are in good agreement with available experimental data and other theoretical results. The relative stability and formation of LaCo13 and La(FexAl1-x)13 phases have been successfully explained. Interesting changes of magnetic properties in an Al doped Fe13 cluster have been obtained. The possible effect of Al on the magnetic phase diagram of La(FexAl1-x)13 is discussed.