Melt derived glasses of (1-x)B 2 O 3 ∙xBi 2 O 3 system with 0.1≤×≤0.875 were investigated by X-ray photoelectron spectroscopy (XPS) in order to evidence the structural changes that occur at the surface of bismuth borate glasses as Bi/B ratio increases from 1:9 to 7:1. The high resolution XPS spectra of O 1s, Bi 4f and B 1s photoelectrons emphasizes consistent changes in the vicinity of oxygen, and small changes around bismuth and boron atoms by increasing of Bi 2 O 3 content. The deconvolution of O 1s spectra was used to investigate the Bi/B ratio effect on the number of bridging and non-bridging oxygens and the results obtained were discussed considering four components occurring from oxygen atoms implied in BOB, BOBi, BiOBi and BO/BiO bonds. From the deconvolution of Bi 4f high resolution spectra, four components related to Bi 0 and bismuth atoms connected in bonds of BiOBi, BOBi and BiO types were identified. It was concluded that boron and bismuth play a network former role in the entire compositional range.