We wish to investigate the composition and temperature dependence of the magnetic structure in YbMn6-yFeySn6 (y 1), the high-temperature ferromagnetic region fully disappears. In all alloys, Yb seems to remain non-magnetic. Powder neutron diffraction is mandatory to determine the spin structure (and its changes with temperature and yFe), to precise the Mn/Fe distribution over the four available crystallographic sites and to confirm the lack of magnetic order of the Yb sublattice.