Aim and Objective: To study the effects of Vitamin B12 deficiency in infants and to see if there were any changes in the findings on treatment on follow up scans. Materials & Methods: We present three cases, children of age 6, 9 and 12 months of age, whose mothers had vitamin B12 deficiency. Patients underwent MRI brain scans after taking proper consent and were followed up after they were treated for deficiency at 12, 6 and 18 months respectively. Result : On admission, the patients showed delayed milestones and were drowsy, hypotonic and lethargic. Serum vitamin B12 levels were below normal limits. On brain MRI images revealed prominent supratentorial subarachnoid spaces and cerebral atrophy. All the three children were treated for vitamin B12 deficiency and follow up MRI scans were done at 12, 6 and 15 months respectively. The follow up scans showed regression in the supratentorial cerebral atrophy in the patients on treatment for vitamin B12 deficiency resulting in reversible atrophy in the MRI scans, hence concluding that atrophy is not a permanent imaging finding once detected in Vitamin B 12 deficient children. Conclusion: Maternal vitamin B12 (cobalamin) deficiency is usually secondary to pernicious anemia or to a strict vegetarian diet and can cause serious neurological abnormalities among exclusively breastfed infants.Brain changes may include diffuse cerebral atrophy, thinning of corpus callosum, cerebellar & spinal cord atrophy and postero-lateral cord hyperintensities. When a child presents with atrophy of the brain, it is usually mistaken as a permanent change causing concern among parents of children.