The present study analyzes the influence of modification of sugar crystallization from three torntwo stages and tried to optimize both sugar and ethanol production from sugar cane source. Thernefficiency of sugar crystallization process was determined by simulation at Wonji Shoa SugarrnFactory (WSSF). Economical advantages in optimizing the sugar and ethanol productions wererncompared with the factoryâ€™s existing working norms. Batch fermentation of molasses samplesrnusing saccharomyces cerevisiae was carried out at fermentation temperature of 30 (+1) o C, pHrnof 5.5 (+ 0.1) and ammonia supplement of 2 g/L in Erlenmeyer flask of 250 mL. The parametersrnvaried were total sugar as invert (TSAI) in the fermentation broth of prepared molasses fromrnboth two and three crystallization stages and the amount of dry yeast in the inoculums (1,3,5rng/L). The measured values were concentration of the produced alcohol and the residual sugar.rnFrom the obtained data of alcohol concentration and residual sugar; the ethanol yield wasrncalculated. All results obtained were subjected to SPSS and significance was set at 5% level.rnAlcohol concentration was found to vary from highest of 83 g/L to lowest of 36 g /L for molassesrnB (mB) and from highest of 53 g/L to lowest of 30 g/L for molasses final (mF), while residualrnsugar concentration varied from lowest of 26 to highest of 73 g/L for mB and 34 to 78 for mF.rnThe calculated ethanol yield varied from highest of 0.47 g/g to 0.19 g/g and from 0.31 g/g to 0.16rng/g for mB and mF respectively. The variation was statistically significant (p rn0.05).unfermentable sugar (%w/w) of 4.64 and 5.55 was obtained fro mB and mF respectively.rnMicroorganismsâ€™ results as total viable count were found as 378 CFU per 10 g of sample for mBrnand 428 CFU per 10 g of sample for mF. The net sugar produced was 12.61 % and 11.76 %rncane from three and two crystallization system, whereas final molasses of 3.73 % and 4.79 %rncane in three and two stage respectively were obtained. In the modification (from three to twornstages), about 6.7% decreases in sugar product, an increase in molasses production quantity byrnabout 28.4% and an increase in molasses TSAI content by about 28.8% respectively werernobtained . The overall economic return by modification of the crystallization system indicatesrnthat there was additional income of 19.83 Eth. birr per ton of cane through optimum productionrnof sugar and ethanol. The obtained results reveal that the modification in sugar crystallizationrnsystem can bring over all improvement in both sugar and distillery plants and foundrneconomically feasible in the studied cases. Besides the economic return, the modification systemrntends to reduce the high recirculation of material, the energy utilization and the crystallizationrnarea capacity than the existing three crystallization system, with out affecting the productrnquality.