Monte Carlo method is often used in radiation therapy as utilized in all the branches of science. For this purpose, various preset codes are used for the dose calculations in radiotherapy. In this study, a new Monte Carlo Simulation Program (MCSP) was developed for the dose distributions of a clinical linear accelerator (LINAC) in water phantom. MCSP was carried out by taking into account the interactions of photons with matter in MATLAB (The Mathworks, Inc.). In the study, 6 MeV (6 MV photon mode) energies of photons are examined. In order to validate the performance and accuracy of the simulation, the experimental measurements and MCSP calculations were compared for both percentage depth dose curves and beam profiles. The Monte Carlo results show good agreement with experimental results. (C) 2014 Nalecz Institute of Biocybernetics and Biomedical Engineering. Published by Elsevier Urban & Partner Sp. z O.O. All rights reserved.