This work represents the extraction of cottonseed oil using subcritical water. The extraction efficiencies of different range temperatures (180-280 degrees C), having mean particle size range from 3 mm to less than 0.5 mm, water:seed ratios of 0.5:1, 1:1, and 2:1, and extraction times in the range of 5-60 min were all investigated. The composition of the extracted oil, using the subcritical water, was analyzed by gas-liquid chromatography and compared with that extracted using traditional hexane extraction. The results showed that the optimum temperature, mean particle size, water:seed ratio, and extraction time were 270 degrees C, <0.5 mm, 2:1, and 30 min, respectively. In addition the extracted oil was identical to that extracted using the traditional hexane method. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 2353-2359, 2011