Cellulosic materials are most abundant biomass in the Earth. Burning of cellulosic materials will release greenhouse gases that cause global warming. Alternative treatment of cellulosic materials biomass should be applied to prevent pollution. On the other hand, succinic acid is one of most desirable chemical with industrial application. Succinic acid can be used as precursor of many bio-based chemicals and polymers. Yarrowia lipolytica PSA 02004 could converted glucose to succinic acid through fermentation. In this study, we focus on bioconversion of cellulosic materials into succinic acid using Yarrowia lipolytica PSA 02004 through fermentation. Firstly, cellulosic materials underwent alkaline pretreatment. After that, pretreated cellulosic materials were adjusted to pH 7 prior for enzymatic hydrolysis. Optimization of enzymatic hydrolysis of pretreated cellulosic materials was performed to obtain optimum concentration of glucose. Parameters for enzymatic hydrolysis optimization included pH of buffer, temperature and concentration of enzymes. Next, pH adjustment and filtration of cellulosic materials hydrolysate were done prior to fermentation. Fermentation of cellulosic materials hydrolysate using Yarrowia lipolytica PSA 02004 for 4 days. Fermentation broth was analyzed using HPLC to determine succinic acid concentration produced. Results showed that optimum pH, temperature and concentration of enzymes for enzymatic hydrolysis of cellulosic materials were found. Fermentation of cellulosic materials hydrolysate using Yarrowia lipolytica PSA 02004 resulted in a succinic acid yield of 0.264 g/g. In conclusion, bioconversion of cellulosic materials into succinic acid using Yarrowia lipolytica PSA 02004 was successfully achieved.