Evolution of structural phases and microstructural cast state of Fe100-(x+y)GaxAly compositions in the range of 17≤(x+y)≤39 at.% was studied in neutron diffraction experiments performed with high resolution and in continuous temperature scanning mode when heated to ~ 900oC and subsequent cooling. It is established that the structures of the cast states of triple alloys in the studied range of Ga and Al content basically repeat the structure of the double compositions Fe100-xGax up to x~ 30 and Fe100-yAly up to y~ 50. Namely, only cubic phases (A2, D03 and B2) are observed in them, and hexagonal (A3, D019) and monoclinic (such as Fe13Ga9 or α-Fe6Ga5) there are no phases characteristic of the Fe-Ga system. The expansion of the range of formation of cubic phases formed on the basis of the BCC cell in ternary alloys in comparison with Fe100-xGax indicates the role of Al in the stabilization of these structures. Keywords: alloys Fe-Ga, Fe-Al, Fe-Ga-Al, structural phase transitions, neutron diffraction, magnetostriction.