Studies on the use of pesticides in southwest Nigeria have revealed a substantial rise in a variety of pesticide-related illnesses, including mental impairment and reproductive problems. Those who work in agriculture and are regularly exposed to pesticides are the most impacted. The World Health Organization (WHO) predicts that three million severe pesticide poisoning episodes occur globally each year, with at least 300.000 deaths and 99% of cases occurring in low-and middleincome nations. The effects of longer-term exposure to pesticides on health are not yet precisely estimated. Objectives: To this end, the objective of this study is to assess the knowledge of pesticide residues and common pesticides in grain-based food (brown and white beans, yellow and white maize, brown millet and rice) about pesticide use in selected markets of Southwest Nigeria. Methods: A total of 240 respondents were selected from four states (Ado-Ekiti, Ibadan, Osun and Ondo) with the aid of structured questionnaire and interview guide using purposive sampling technique. The markets were Oja-titun (market) Ile