FTIR spectroscopy measurements were performed on the xGd2O 3-(100-x)[2Bi2O3·B2O 3] system with 0 ≤. × ≤. 25 mol% in order to point out the effect of Gd2O3 addition in the bismuth-borate glass matrix on the local order of this system. FTIR spectroscopy data suggest that the gadolinium ions play the network modifier role in the studied glasses. These data show that the glass structure consists on the BiO6, BO 3 and BO4 structural units, and the conversion among these units mainly depends on the Gd2O3 content.