Kenyans have been highly affected by aflatoxicosis for a long time because of excessive exposure to high aflatoxin containing maize-based products. Maize has been the staple food in Kenya which is more highly consumed than any other cereal product. Many countries with strict aflatoxin threshold application, have consumers who still consume maize-based products, which has not gone through testing. The more remote and lower income areas are more affected by untested maize, ending up exposing themselves to Hepatocellular carcinoma which is a health hazard. The study was designed to determine the exposure of aflatoxin in Kiandutu slum which is a marginalized area in Thika, Kiambu County, Kenya. Ninety seven households were used in the study where number of maize-based products obtained from each household was sampled. Quantitative analysis was used to determine the aflatoxin levels by use of ELISA method. Questionnaires were used to collect the consumption data and sampling of maize- based products was done purposively. Aflatoxins were found in 30.93% of maize flour at between 0 to 34.19 μg /kg, 29.33% of composite flour at between 0 to 30.06 μg /kg, 18.67% of maize grain at between 0 and 20.92 μg /kg and 6.97% of Muthokoi at between 0 to 7.14 μg /kg. Across all sampled households, daily consumption of maize-based products in kilograms per body weight was found to be highest in maize flour, followed by whole maize grains, composite flour and muthokoi in that order. Monte Carlo risk simulation was used to generate the quantitative exposure data. Daily maize flour consumption was higher than other maize-based products with a mean of 0.0038 kg/kg bw/day. It also had the highest daily aflatoxin exposure at a mean of 0.0301 μg/kg/bw/day. The percentage level of the health risk was found to be highest through maize flour consumption at 68.65. Results showed that the frequency of consumption of maize-based products is an important contributor to dietary exposure risk