IntroductionFarm workers are at a very high risk of occupational diseases due to exposure to pesticides resulting from inadequate education, training and safety systems. The farm worker spends a lot of time exposed to these harmful agrochemicals. Numerous acute cases with symptoms typical of agrochemical exposure were reported from the commercial farms. We assessed the health effects of agrochemicals in farm workers in commercial farms of Kwekwe District (Zimbabwe), in 2006.MethodsAn analytical cross sectional study was conducted amongst a sample of 246 farm workers who handled agrochemicals when discharging their duties in the commercial farms. Plasma cholinesterase activity in blood specimens obtained from farm workers was measured using spectrophotometry to establish levels of poisoning by organophosphate and/or carbamates. Information on the knowledge, attitudes and practices of farm workers on agrochemicals use was collected using a pre-tested interviewer administered questionnaire. Bivariate and multivariate analyses were conducted to determine factors that were associated with abnormal cholinesterase activity.ResultsThe prevalence of organophosphate poisoning, indicated by cholinesterase activity of 75% or less, was 24.1%. The median period of exposure to agrochemicals was 3 years (Q1:=1 year, Q3:=7 years). Ninety eight (41.5%) farm workers knew the triangle colour code for the most dangerous agrochemicals. Not being provided with personal protective equipment (OR 2.00; 95% CI: 1.07 – 3.68) and lack of knowledge of the triangle colour code for most dangerous agrochemicals (OR 2.02; 95% CI: 1.02 – 4.03) were significantly associated with abnormal cholinesterase activity.ConclusionThere was organophosphate poisoning in the commercial farms. Factors that were significantly associated with the poisoning were lack of protective clothing and lack of knowledge of the triangle colour code for most dangerous agrochemicals. We recommended intensive health education and training of farm workers on the use of agrochemicals, provision of adequate and proper personal protective equipment as mitigation measures to this problem.