The emission spectra of YVO4:Ln3+ (Ln3+ = Eu3+, Sm3+ or Dy3+) phosphors both singly doped and co-doped with Bi3+ have been investigated in different experimental conditions in order to assess the effect of the co-doping ions on the luminescence properties. The experimental results have been analyzed in the light of the literature information available on these materials. The role of the Bi3+-V5+ charge transfer state and its influence on the emission properties has been stressed and discussed in details.