Low-temperature hydrothermal treatment of waste biomass (sawdust) was performed using an autoclave at various temperatures of 180, 250, and 280 degreesC for 15 min and 60 min. The oil product was obtained from both liquid and solid portions of reaction products from the autoclave, and the composition of oil products was investigated separately. At high reaction temperature, i.e., 250 degreesC and 280 degreesC, the longer reaction time led to decreased oil yield; at low reaction temperature (180 degreesC), the oil yield was found to increase with the increase of reaction time. The oil1 (extracted from the liquid portion) consists of low-boiling-point compounds, whereas oil2 (extracted from the solid portion) contained both low- and high-boiling-point oxygenated hydrocarbons. Ca(OH)(2) was found to be effective on liquefaction of biomass in terms of both oil yield and composition. The volatility distribution of oxygenated hydrocarbons in oil1 and oil2 was studied by using a C-NP gram which can be used as a tool for characterizing biomass-derived oil products.