This paper examines the applicability of Okumura-Hata model in Oman in GSM frequency band. The study was carried out for open area only, since measurements provided from OmanMobile were about the open areas. The mean square error (MSE) was calculated between measured path loss values and those predicated on basis of Okumura-Hata model for an open area . The MSE is up to 6dB, which is an acceptable value for the signal prediction . Therefore, the model gave a significant difference in an open area that allowed necessary changes to be introduced in the model. That error was minimized by subtracting the calculated MSE (15.31dB) from the original equation of open area for Okumura-Hata model. Modified equation was also verified for another cell in an open area in Oman and gave acceptable results.