Photoluminescence spectra of Mg doped silicon samples has been studied. Two sets of samples, reference and plastically deformed, were doped with Mg under identical conditions, The luminescence spectra of the reference samples revealed a set of lines in the region 1?1.07 eV but no radiation expected for recombination of an exciton bound to Mg donor was found. From the energy position and temperature behavior a part of these lines were attributed to the recombination of free and bound excitons with a simultaneous excitation of the Mg⁰ donor. Unlike the reference samples no such lines were found in the deformed samples with the exception of a weak line at the energy position close to the expected one for an exciton bound to the Mg⁰ center and an additional emission overlapping the dislocation related lines D1 and D2. The latter was assumed to originate from the recombination at Mg?dislocation complexes.