Electronic structure calculations are carried out for the ferromagnetic GdM2 compounds (M=Mg, Al, Fe, Co, Ni, Rh, Ir, Pt). By using the calculated susceptibilities, densities of electronic states, and exchange parameters, the Curie temperatures were evaluated for these compounds in the framework of a modified molecular-field approach. The calculated magnetic ordering temperatures appeared to be in improved agreement with experimental data, in contrast to the results obtained within a conventional mean-field theory.