We report the case of a 7-month-old child who presented with regression of milestones, seizures, altered sensorium, and vomiting. An elder sibling had died of similar complaints. Lead encephalopathy was considered because of presence of microcytic hypochromic anemia and dense metaphyseal bands on wrist radiogram. Magnetic resonance imaging (MRI) of the brain revealed diffuse dysmyelination involving both periventricular and subcortical white matter. Such diffuse changes have not been described previously. The child's father was operating an illicit lead-acid battery manufacturing unit at home. The child was subjected to chelation therapy, which was accompanied by environmental exposure source modification. He showed significant improvement. Our case highlights the importance of taking a detailed occupational history and considering lead poisoning in the differential diagnosis of encephalopathy of unidentifiable cause.