1. Data on deaths from pesticide poisoning occurring in England and Wales between 1945 and 1989 (no data are available for 1954) have been collated; pesticides were responsible for only 1012 (1.1%) of the 87,385 deaths from poisoning (excluding those due to carbon monoxide) occurring over this 44 year period. At least 73% of all pesticide fatalities were due to suicide and overall there was a predominance of males (male:female ratio 2.4:1). No deaths from pesticide poisoning in children under 10 years have been reported since 1974 although almost 50% of suspected pesticide poisoning incidents involve this age group. 2. Herbicides were responsible for 787 (78%) fatal poisonings, 110 (11%) were caused by insecticides, 69 (6.8%) by rodenticides, 30 (3.0%) by wood preservatives and 16 (1.6%) by other pesticides. 3. The herbicide, paraquat, was responsible for 570 of 1012 (56%) deaths and, although there has been a progressive decline in the annual number of deaths from paraquat poisoning since 1982, paraquat remains the most common cause of fatal pesticide poisoning in England and Wales. 4. Sodium chlorate caused 113 (11.2%) deaths, most of these fatalities occurring between 1965 and 1983; only one death has been recorded since 1984. The phenoxyacetate herbicides resulted in 50 deaths; 2,4-D was implicated most commonly. Sixty-eight deaths were due to organophosphorus insecticides; demeton-S-methyl, malathion and mevinphos were involved most frequently. Only eight deaths resulted from organochlorine insecticides and two of these also involved an organophosphorus insecticide.(ABSTRACT TRUNCATED AT 250 WORDS)