Geostatistical conditional simulation is widely used and accepted as a method of generating stochastic models of hydrocarbon reservoirs. There are many applications described in the literature using one or more of the range of methods now available, and apart from the petroleum reservoirs, simulated annealing technique is applied to the total organic carbon values of the potential hydrocarbon source-rocks which has been penetrated by seven wells drilled on the western Taurus region. The main source rock intervals are mostly encountered in the autochthonous Beydaglari carbonates. After a description of the geology of the area a geostatistical study based on 440 composite samples is presented. The composite samples gave a positively skewed distribution with a mean of 0.27% total organic carbon values. Experimental variograms representing three main directions-strike plunge, cross dip, and downdip directions-were calculated a spherical type model was fitted to variograms. A model validation and a number of conditional simulation were applied to the data, respectively and the best simulation senario was chosen. Thus, a total of 1440 000 grid nodes were conditonally simulated using the set of 440 data values. Simulation results indicate that the amount of organic matter that has generated hydrocarbons increases with increasing depth and significant source rocks rich in organic matter has concentrated on the coastal area of the western Taurus region.