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Lithology is an important input parameter into petroleum system modelling (PSM) as it carries information about thermal conductivity and reservoir quality. It can be obtained from the geological static model, gross depositional environment (GDE) maps, or seismic data. The objective of this study is to demonstrate the influence of lithology input on the PSM simulated models (pressure and temperature), by comparing the lithology input derived from seismic data against the one inferred from GDE maps, using S-field as case study. The derivation of lithology information (Vshale) from seismic data is attempted using extended elastic impedance (EEI) inversion followed by normalization. We performed conversion of Vshale cube into the depth domain, then upscaling prior to utilization as input in PSM for the model simulation and calibration. The results of pressure and temperature models achieved using the lithology input from the GDE maps (homogeneous lithology assumption) served as the reference. These results are compared to the simulated pressure and temperature models obtained using Vshale cube as the lithology input parameters. 3 wells (SD-2, SD-1, S-5) available in S-field (located in Malay Basin) for the study. SD-2 is the calibration whereas SD-1 and S-5 are the blind tests for pressure and temperature models. The pressure model obtained using the seismic lithology cube shows better matching with the measured pore pressure data points when comparing to the pressure model achieved from the reference input. By quantifying the average error between the pressure model and the actual pressure data, the former lithology input contributes to lower pressure error of 161psi in contrast to 232psi using the later lithology input. The results from the blind tests show consistent findings with SD-2 where the lithology input from Vshale cube indicates better agreement with the measured pressure data as compared to the one obtained from GDE maps. The average pressure error has decreased from 220psi to 140psi and from 465psi to 296psi for SD-1 and S-5 respectively. From the temperature model perspective, subtle differences observed for the models for both types of lithology inputs. Both types of lithology inputs able to match well with the recoded temperature data points. In summary, integrating seismic lithology cube into PSM able to provide improved prediction due to detailed characterization of lithology distribution. The paper has illustrated an attempt to leverage on seismic data for the derivation of lithology (Vshale) cube and using it as a lithology input for petroleum system modelling. The Vshale cube provides detailed and improve characterization of lithology distribution, which will influence the output of the simulated models from PSM as shown through the pressure and temperature models. This could be helpful information for well planning and drilling.