Characteristic odour components of Citrus inflata Hort. ex Tanaka (Mochiyu) were studied by sensorial and instrumental techniques. Flavour dilution (FD) factor and relative flavour activity (RFA) of individual volatile components were evaluated by aroma extraction dilution analysis (AEDA) and gas chromatographyolfactometry (GC-O). The results indicated that hydrocarbons (98.1%) made up most of the oil: monoterpenes and sesquiterpenes were 97.6% and 0.5%, respectively. Among oxygenated compounds, linalool (0.2%) as an alcohol, perillaldehyde (0.1%) and tridecanal (0.1%) as aldehydes showed relatively high quantities, while the others were all less than 0.05%. AEDA and GC-O indicated that myrcene, (E)-ocimene, cis-linalool oxide, trans-linalool oxide, beta-copaene, perillaldehyde and perillyl alcohol were the odour characteristic compounds, showing Mochiyu-like odour. Careful sniff testing revealed that (E)-ocimene could be an key odour compound of Mochiyu aroma. Copyright (C) 2003 John Wiley Sons, Ltd.