This work investigated the extraction of cashew nut shell liquid (CNSL) using supercritical carbon dioxide (SC-CO2). Effects of process parameters such as extraction pressure, temperature and flow rate of SC-CO2 were investigated. The yield of CNSL increased with increase in pressure, temperature and mass flow rate of SC-CO2. However, under different operating conditions, the composition of CNSL varied. The study of physical properties and chemical composition of the oil obtained through super critical fluid extraction (SCFE) showed better quality as compared to the CNSL obtained through thermal route. Experimental results were compared with diffusion based mass transfer model. Based on this simple model, extraction time was optimized. (c) 2005 Elsevier Ltd. All rights reserved.