We have examined the characteristics of the magnetic order present at room and lower temperatures in disordered samples corresponding to the Fe0.9−xMn0.1Alx (0.1⩽x⩽0.5) series prepared by arc melting, high temperature homogenization, and quenching. To that purpose we have measured the compositional variation of the lattice parameters, the Mössbauer spectra, the high field magnetization, and the saturation coercivity and also the compositional and temperature dependences of the magnetic susceptibility and the low field magnetization. Our results are summarized in a magnetic phase diagram including ferromagnetic, paramagnetic, pure spin glass, and reentrant spin glass regions.