During process of fermentation a variety of parameters effect on ethanol production, current work focusses to investigate the effect of different carbon sources on ethanol production using numerical simulation. The fermentation process was carried out using microprocessor-controlled fermenter in which different types of carbon sources were studied like glucose, sucrose and molasses from 10% to 15% of range. The model proposed by Monod was found to be more appropriate for describing the batch growth and ethanol production using kluyveromyces marxianus. The maximum yield of ethanol production took place using 15% molasses as carbon source. The maximum ethanol production (76 g/l) was observed at 15% molasses, as for sucrose and glucose are concerned it gives lower value of ethanol production up to 73g/l by keeping other operational parameter under optimized condition such are 35oC, 300rpm, 0.2 vvm/l and pH5. 5. Approximately same results were achieved by using experimental data and model execution.