African Journal of Agricultural Research 2011, Vol. 6(10): 2216-2230This study was conducted to assess farming practices, agrochemical usage and environmental pollution in Manyara basin, Tanzania. Field surveys, interviews, questionnaires and Lake Manyara nutrient analysis were used in data collection. The highest number (95%) of households grew crops, namely, maize, rice, banana and vegetables with median farm size of 3 ha. Irrigated farming was common (75%) which enhanced cultivation on same piece of land up to 6 times a year. Farmers indiscriminately used pesticides, namely, insecticides (50%), fungicides (37.5%) and herbicides (12.5%). Uses of endosulfan in vegetable farms poses public health threats to consumers. Most respondents (85%) applied insecticides in vegetables up to 4 times per cropping season. Excessive use of pesticides and haphazard disposal of pesticide remnants and containers caused environmental pollution. The average amount of acaricides used was 1109±915 ml (mean ± SD) per livestock keeper per month per. Most farmers (78%) used inorganic fertilizers and animal manure (43.4%). Low levels of ammonium (3.6±3.1 μg/L), nitrate (1±0.8μg/L) and phosphate (36.1±42 μg/L) were recorded in the lake. Easy access to agrochemicals, limited knowledge of pesticide on environmental health and limited extension services were factors for indiscriminate uses of agrochemicals. Increasing farmers awareness and training aimed at sustainable agriculture, agrochemical uses and integrated pest management is suggested.