SummaryChlorpyrifos (Spannit 48% e.c.; PBI) was applied at the recommended rate of 0.72 kg a.i./ha to two pastures on which either Brent Geese (Branta bernicla) or Canada Geese (Branta canadensis) were grazing. Observations of the number of geese and their behaviour were made on two or three occasions before spraying and four or five occasions after. Observations enabled an activity index and a count of pecks/minute to be calculated. No changes in the numbers or behaviour of the geese that could be attributed to chlorpyrifos application were found. Thorough searches were made for cadavers of the experimental fields, their environs and the roosts the day after other observations were made. Only one cadaver was found which had died as a result of swallowing angling equipment. Samples for chlorpyrifos residue analysis in the herbage and goose faeces showed no chlorpyrifos to be present prior to spraying the fields and that the chemical was present after spraying in both the herbage and faeces but fell to negligible levels within a few days. At least in the short‐term, chlorpyrifos application to pasture appeared to have no perceptible or statistically significant effect on goose behaviour or well‐be