The “shrimp mushroom”, Russula xerampelina, has a strong cooked shellfish odour. Headspace volatiles from fresh sporocarps of this mushroom were analysed using solid phase microextraction (SPME) and gas chromatography–mass spectrometry (GC–MS). Trimethylamine and trimethylamine N-oxide were the only volatile compounds detected emanating from the fruiting body. Trimethylamine is noted for its fishy, cooked crab or cooked shrimp-like odour.