IntroductionLead exposure is toxic to all humans and is very harmful to young children, especially 5-year-olds. Elevated blood lead levels (BLLs) in children have been associated with their daily surrounding environment. This protocol seeks to evaluate the association between environmental lead exposure and BLLs among children in day-care centres, including household and other risk factors.Methods and analysisTo achieve the objectives of the study, we adopted a cross-sectional analytical design. A portable X-ray fluorescence analyser was used for environmental sampling, and BLLs were determined using the LeadCare II machine among preschool children. Household and other risk factors were assessed using a questionnaire. Random sampling was employed to select day-care centres in the municipality and children in each day-care centre. Data will be analysed using SPSS V. 26.Ethics and disseminationEthical approval and permission were obtained prior to commencement of the study. The researcher intends to publish the results in peer-reviewed journals and also to present a paper at a scientific conference. The study will generate information on environmental lead exposure among vulnerable children (2–5 years), and it will promote public health action to prevent long-term exposure in day-care centres.