A study was undertaken to obtain information on farmers' knowledge, attitudes and practices regarding pesticide usage and to determine the amount of pesticide in soil and water samples collected at four cotton producing areas of Mali. The results from a survey of 24 farmers identified various concerns regarding personal and environmental safety. Despite their training, sometimes growers did not use pesticides in an appropriate manner. Highly toxic pesticides are used by farmers with insufficient personal protective equipment. Sixty soil samples and eight water samples from four cotton growing areas in Mali were scanned for detectable levels of fifty pesticides in total. Pesticides were detected in 77% of the soil samples and the main pesticides were p,p-DDT and its breakdown products, endosulfan I endosulfan II, endosulfan sulfate and profenofos. Among the pesticides detected, p,p-DDT use in the study area had not been reported during the past ten years. The most common pesticide detected in the soil samples from cotton growing areas studied was endosulfan II constituting 65% of the detections with a maximum amount of 37 ng/g. Residues detected in soil samples were below the quantification limit for the newer cotton production region of Kita and for the intermediate region of San. Eight pesticides were detected in water samples: γ-BHC (lindane), endosulfan I, endosulfan II, endosulfan sulfate, dieldrin, p,p-DDD, p,p-DDE and atrazine. All detected pesticides in water had concentrations below the quantification limit except for atrazine. Even though pesticides were found at low concentrations in ground water samples, the fact that water from these wells is used for human and animal consumption is of concern. Also, soil pesticides may be taken up by plants and passed on to other organisms feeding on those plants. Further residues studies in the cotton growing areas of Mali are in order to monitor pesticides residues in Malian soils, water and living organisms. / Master of Science