The extraction of aliphatic hydrocarbons from the Niger Delta sedimentary organic matter by supercritical carbon dioxide at different extraction temperatures and times is described. The study was undertaken in order to determine optimal extraction conditions for the Niger Delta organic sedimentary rock. The results showed that the extraction temperatures (65, 95, 125, 155 and 185 degrees C) and kinetic rates have a significant effect on extraction yields. The optimum temperature (185 degrees C) for supercritical fluid extraction of Niger Delta rock was different from that obtained for rock samples from other basins. In comparison with soxhlet extraction, supercritical fluid extraction has better yields; the relative recoveries of the analytes from SFE are about 81-99% in excess of that of soxhlet extraction. (C) 2007 Elsevier B.V. All rights reserved.