Oxyfluoride glass system based on 60B(2)O(3)-(40 - x)PbO-xPbF(2), where x = 0, 5, 10, 15, 20 and 25 mol% was prepared. The density of each glass was measured and the molar volume was calculated. The velocities for both the longitudinal and the transverse ultrasonic waves were measured by using the pulse-echo technique. The longitudinal, shear, Young's and bulk moduli were calculated from the measured velocity and density values. Makishima and Mackenzie's theory was applied to calculate the elastic moduli of the present glasses. The calculated values are consistent with the measured ones. The measured and the calculated moduli were correlated for the composition of the glasses as a function of PbF2 content and they are increased with increasing PbF2. This is due to some structural changes which occur upon replacing PbF2 instead of PbO content in the glass matrix.