The effect of different cooking methods on the flavour of mushroom soup was assessed. The results indicated that the levels of free amino acids and 5'-nucleotides in the microwaved mushroom soup were (P < 0.05) higher than those in boiled and autoclaved mushroom soup. The number of volatile compounds identified in the boiled mushroom soup was (P < 0.05) higher than those in autoclaved and microwaved mushroom soup. The main aroma-active compounds found in mushroom soup were 1-octen-3-one (mushroom-like), 3-octen-2-one (cooked mushroom-like), 2,6-dimethyl pyrazine (roast nut), benzeneacetaldehyde (floral), dihydro-5-methyl-2(3H)-furanone (sweet) and some unknown compounds with popcorn and sauce flavour. In addition, boiled, autoclaved and microwaved mushroom soup possessed thirteen, ten and nine aromaactive compounds (with flavour dilution factors > 1), respectively. Thus the flavour of mushroom soup is dependent on the cooking methods as proved by gas chromatography and olfactometry analysis.