Sweet sorghum has the prospect of being used as a source of food, feed, and fuel (ethanol). The high sugar content in sweet sorghum stalk can be fermented to ethanol through yeast fermentation. In this study the performance of two yeast strains (Saccharomyces cerevisiae InaCC Y653 and Saccharomyces cerevisiae InaCC Y586) in enhancing the ethanol production either using a free cell or an immobilized cell system was evaluated. Calcium alginate was used as the matrix for cell immobilization. Fermentation was carried out in the batch process for 72 h, the concentration of ethanol and sugars were determined by Gas Chromatography (GC) and High-Performance Liquid Chromatography (HPLC), respectively. The highest bioethanol production was obtained from sweet sorghum juice fermented using S. cerevisiae Y586 in a free cell system, which was 35.01 ± 0.01 g/L or 0.48 ± 0.06 g/g in ethanol yield. The free cell system gives the best result than the immobilized cell system. The immobilization system by using Ca-alginate matrix did not improve the ethanol production. Optimization of some immobilization parameters should be done for further study.