In the presented study, a code was created for the purpose of true coincidence summing (TCS) correction factors for Cs-134. The created code was implemented in EGS4 Monte Carlo simulation package. TCS factors were determined for nine different energies for different detector-source geometries. The calculated results were successfully validated by an empirical method using a point Cs-134 radioactive source and a p-type HPGe detector having 55% relative efficiency. Although the code created gives TCS factors only for Cs-134 the technique presented can be used to obtain the factors for any radionuclide used in gamma-ray spectrometry. (C) 2015 Elsevier Ltd. All rights reserved.