Background and Objective: Lead is a ubiquitous environmental pollutant affecting the central nervous system. Many studies have provided evidence that exposure to lead causes reduced cognitive performance or structural changes in the brain. Despite these neuroscientific studies, no study has yet investigated the association between body lead level and the brain electrical activity (which indicates cognitive dysfunction in the brain). This study examined the association between blood lead level and electroencephalography (EEG) in cognitively unimpaired older adults. Methods: A total of 93 cognitively unimpaired older adults (60 years or older) was included in this study. The level of cognitive function or impairment was evaluated by neurologists diagnose. EEG is a non-invasive method that records the brain electrical activity via electrodes placed on the scalp. A cap-type wireless EEG device was used for EEG recording, with linked-ear references based on a standard international 10/20 system. Blood lead levels were measured by inductively coupled plasma mass spectrometry. Multiple linear regression was employed to analyze relationships between lead and EEG features of the frontal, central, parietal, temporal, and occipital regions. Results: The mean age of study population was 71.5 years, and 46.2% were female. The mean blood lead level was 1.60 µg/dL. We found a significant association between lead and EEG features. Specifically, elevated blood lead levels were significantly and negatively associated with EEG activity in the brains central, temporal, and occipital regions. The most robust finding was observed in occipital lobes, which are located at the very back of the brain and responsible for the visual processing area of the brain. The association was independent of covariates (i.e., age, gender, income, health behaviors, and chronic conditions). Conclusions: Environmental exposure to lead may be associated with cognitive performance via reduced brain electrical activity in the central, temporal, and occipital lobes.