A column soil elutriator (the Wye Washer) for extracting cyst nematodes and other small invertebrates from soil samples is described. Laboratory tests have shown the new equipment to achieve extraction rates equal to or better than existing techniques and to offer operational advantages also. Soil in quantities of up to 1 kg may be processed without drying or subsampling, the equipment can be left unattended once set to work, and can be used to extract a range of target organisms. There is only one working part (a valve) and no electrical parts, but water use and price is high. The Wye Washer is now used in the advisory entomology laboratory at Wye as the standard equipment for extracting cysts of Heterodera and Globodera, for eggs of cabbage root fly (Delia radicum) and for cocoons of black currant leaf midge (Dasineura tetensi).