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The observed 511 keV line from the Galactic Bulge is a real challenge fortheoretical astrophysics: despite a lot of suggested mechanisms, there is stillno convincing explanation and the origin of the annihilated positrons remainsunknown. Here we discuss the possibility that a population of slowlyevaporating primordial black holes with the mass around $10^{16}-10^{17}$ gejects (among other particles) low--energy positrons into the Galaxy. Inaddition to positrons, we have also calculated the spectrum and number densityof photons and neutrinos produced by such black holes and found that thephotons are potentially observable in the near future, while the neutrino fluxis too weak and below the terrestrial and extra--terrestrial backgrounds.Depending on their mass distribution, such black holes could make a smallfraction or the whole cosmological dark matter.

Primordial black holes and the observed Galactic 511 keV line