Abstract: Background: Impaired cognitive performance remains a major public health problem in developing countries due to emerging evidence from literature suggesting that environmental exposure to chemical substances influences neurocognitive development in children. Cognitive performance was evaluated in 6 domains (Viz., memory, coordination. Language, learning, cognition an academic abilities). There is strong evidence that, memory skills among pupils in mining communities is impaired as compared to their counterpart in non-mining communities. On the other hand, pupils in school with reliable source of water performed better in their academic function. Even though the current study looked at different factors with respect to cognitive impairment; teachers and pupils ratio per school, nutrition status and availability of water sources showed significant results. Objectives: The objective of this study was to determine the prevalence of cognitive impairments and associated factors among primary school children aged between 8 and 12 years in mining and non-mining communities. Methodology: Cross sectional, school-based design on purposely selected primary schools in Geita District. Primary School Children between 8 and 12 years were recruited for cognitive performance and associated factors. Results: A total of 865 primary school pupils were recruited for study in area with and those without mining activities. Among of the pupils recruited, 443 were boys’ and 422 were girls. There was no significant differences in cognitive impairment in report to sex and age distribution in different domains (Viz., Language, learning, cognitive, and academic) are quite high among the studies school children in Geita as compaired to the general population of cognitive impairment of 10%. Looking at learning impairment alone, the general cut off as documented elsewhere is 12.8%. The current study indicates significant results regarding memory impairment among pupils in mining communities (8%) as compared to non-mining communities (4%) (P-value = 0.005). Conclusion: A significant finding has found on cognitive performance impairment in different aspects such as memory, language, learning, cognitive and academic, of which the majority were mild. It was revealed that 0.5% to 1% population had severe cognitive and academic impairment. There was relatively higher memory impairment among the pupils in mining areas as compaired to non-mining areas (P-value = 0.005).