Abstract: The optimization of fermentation medium conditions for ethanol yield by Saccharomyces bayanus was investigated in simultaneous saccharification and fermentation process using pretreated sugarcane bagasse as carbon source. The FTIR spectrum of pretreated sugarcane bagasse was compared with standard cellulose library. The spectra of 1048 cm-1 for C-O stretch in cellulose and hemicellulose was observed in treated bagasse. The culture parameters, such as temperature, agitation, incubation time and yeast inoculum level, were optimized for enhancing ethanol yield by using central composite experimental design. The optimal level of each parameter for maximum ethanol yield by the yeast was determined. Predicted ethanol yield was highest (39.63 g L-1) with the actual yield of (43.26 g L-1) from 100 g L-1 treated bagasse at the temperature (37.5°C), agitation (100 rpm), incubation time (64 h) and yeast inoculum level (10%). The model computed for R2 value was 0.9555% indicating that it was appropriate and could be useful to predict the levels of variables to achieve maximum ethanol yield. Validation of predicted results was done and the experimental values correlated well with that of predicted results.