A survey of forty French departments shows that only ten of these have undertaken desludging of ponds - since 1980 fourteen primary, 19 secondary and 12 aerated ponds have been desludged. For the primary ponds a sludge accumulation rate of 2.8 cm/year corresponding to 0.12 m "SUP 3" of sludge per inhabitant per year has been calculated. The sludge, usually removed by pumping, with or without draining of the pond, is most easily disposed of by land spreading despite its low fertilizing capacity. Sludge quality and costs are evaluated. (R.H.)