Estimates are presented of the overall extent and cost of farm accidents in Great Britain. Information was obtained on all 56 fatal accidents and on 791 non-fatal accidents reported to the Health and Safety Executive between 1 July 1981 and 30 June 1982. Visits were made to 805 farms to obtain information on unreported accidents. It is estimated that around 85000 accidents occurred on British farms in the survey year, an overall rate of 0·72 accidents per holding. About 60% of the accidents involved personal injury. Half the accidents involved tractors and field machinery. Under the regulations prevailing at the time, only 5% of the accidents were reportable. The total cost of these accidents to the British economy is estimated to be £94 million, with £62 million of this being borne by the farmer/employers. Damage to property was the predominant cost element at £44 million, accounting for nearly half the overall cost.