Fossil grazing traces of molluscs are regularly encountered but have not yet been studied in detail. This paper presents data on the grazing traces produced by a periwinkle (Littorina littorea) and by a chifon (Lepidochitona cinereus) both under laboratory conditions and in the Dutch Wadden Sea. It is found that the traces are different for both species, but that the traces made by one particular species are not necessarily uniform.