Acoustic Emissions were monitored during deformation of polycrystalline Fe-3% Si samples which were strained by 5% and aged at 353 K for various lengths of time. The aim of this study was to resolve whether the deformation mechanism in such samples is by dislocation unpinning from impurities, or by the creation of dislocations at points of stress concentration, or both. After comparing AE from well-annealed samples (where the creation of dislocations takes place at a grain boundary only) and from strain-agdd samples, it is interpreted that for aging times 0 to ≈200 min both the unpinning of weakly pinned dislocations and the creation of dislocations at stress concentrations contribute to deformation. However, with longer aging times, the latter seems to contribute more and more until beyond ≈200 min, when all the deformation could occur by such a process. AE were analyzed in terms of their average amplitude, peak amplitude and frequency spectrum.