Binary xCdO–(100−x)B2 O3 glasses (45 mol% ≤ x ≤ 90 mol%) were successfully prepared by the melt-quenching technique. The effect of CdO on structure and elastic properties of the borate network was studied by using ultrasonic pulse-echo technique. Density and molar volume of the glass show an increase with increasing CdO content, whereas, ultrasonic velocities, elastic moduli, micro-hardness and Debye temperature revealed a broad peaks around 75 mol% CdO. These f indings were interpreted in terms the types of the basic structural units that composing the glass network. In the com position range 45 mol%≤x≤75 mol%, the addition of CdO, a network modifier, resulted in formation of extra bridging oxygens due to BO3 ÆBO4 conversion and, which expands the borate network and stiffening the structure. Beyond x=75 mol%, some of CdO4 structural units and weaker B–O–Cd linkages are formed, besides the creation of NBOs. This opens the structure and decrease the rigidity of the glass. Correlations between elastic properties and compositional parameters are achieved by applying the ring deformation model and Abd El-Moneim’s approach