We present a Monte Carlo study of the room temperature magnetic properties of quenched-disordered Fe1−qAlq alloys with 0⩽q⩽0.6. Simulations were performed using a random site-diluted classical Heisenberg model with nearest neighbor interactions, and using Metropolis dynamics. Results for the Al concentration of the magnetization and susceptibility predict the occurrence of a critical concentration qc at around 40 at. % Al, at which a transition from a ferromagnetic state (q<qc) to a paramagnetic one (q⩾qc) takes place. The simulated dependence of the average magnetization on the Al content is compared with experimental results of the average hyperfine field obtained by Mössbauer spectroscopy. Finally, an analysis of the finite size scaling properties of this system is presented.