The selective extraction of nimbin, salannin, azadirachtin and oil from Neem seeds, using supercritical carbon dioxide and supercritical carbon dioxide:methanol, has been investigated using various conditions. Extraction for 30 min with 100% carbon dioxide using a capillary restrictor to maintain the critical pressure removed only small amounts of oil and triterpenoids. Slightly higher levels of oil and triterpenoids were removed when a backpressure regulator was used. Over a 150 min period, in 30 min intervals, 100% carbon dioxide extracted all the nimbin and salannin from the seeds, whilst leaving some azadirachtin behind. Using carbon dioxide:methanol, no conditions were found which would allow the selective extraction of azadirachtin. However, the highest pressures (34.4 MPa) and percentages of methanol (20%) removed the most azadirachtin in this experiment. An optimum was observed for extracting nimbin and salannin at 20.6 MPa and 6% methanol. © 1997 John Wiley & Sons, Ltd.