In Radiation Therapy efficiency and precision should be conserved so, there is a need to consider the parameters such as PDD and TMR. TMR is an important dosimetric function which can be measured experimentally and can be calculated from PDD by considering scatter factors. The purpose of this study was to compare and verify the accuracy of TMR data calculated using PDD with measured TMR data for 6 MV and 15 MV photon beams. The PDD values were measured at Source to Surface Distance, 100 cm for various radiation field sizes and depths. For the same field size, depth and energy, the TMR values were measured at Source to Axis Distance of 100 cm. The verification of the calculated TMR data was achieved by comparing it with the measured TMR data. The results had shown that; At the initial depths upto 7 cm, both the calculated and measured TMR were in good agreement, but the deviation increases as a function of depth, especially for the smaller field sizes. It can be concluded that; The calculated TMR values and RFA measured TMR data are having a good agreement and significant variations are indicated at increased depths of smaller field sizes.