This review examines the long-term effects of iron deficiency in infancy, highlighting cognitive, motor, and social-emotional impairments, as well as persistent neurophysiological differences. Studies in human infants and animal models suggest that iron deficiency during brain development affects neurometabolism, myelination, and neurotransmitter function. Key findings include lower IQ scores, poorer motor skills, and social-emotional difficulties in children who experienced iron deficiency in infancy. Neurophysiological measures such as auditory brainstem response and visual evoked potentials show altered conduction times, indicating long-lasting changes in neurotransmission. Animal studies further support these findings, showing that early iron deficiency leads to reduced brain iron, altered myelin content, and changes in neurotransmitter systems. These effects are thought to be due to the timing, severity, and duration of iron deficiency, and they persist into adulthood, contributing to chronic disorders of dopaminergic and corticostriatal function. The review also discusses the potential mechanisms underlying these long-term effects, including altered gene and protein profiles, and the impact of iron deficiency on experience-dependent processes such as dendritic arborization.This review examines the long-term effects of iron deficiency in infancy, highlighting cognitive, motor, and social-emotional impairments, as well as persistent neurophysiological differences. Studies in human infants and animal models suggest that iron deficiency during brain development affects neurometabolism, myelination, and neurotransmitter function. Key findings include lower IQ scores, poorer motor skills, and social-emotional difficulties in children who experienced iron deficiency in infancy. Neurophysiological measures such as auditory brainstem response and visual evoked potentials show altered conduction times, indicating long-lasting changes in neurotransmission. Animal studies further support these findings, showing that early iron deficiency leads to reduced brain iron, altered myelin content, and changes in neurotransmitter systems. These effects are thought to be due to the timing, severity, and duration of iron deficiency, and they persist into adulthood, contributing to chronic disorders of dopaminergic and corticostriatal function. The review also discusses the potential mechanisms underlying these long-term effects, including altered gene and protein profiles, and the impact of iron deficiency on experience-dependent processes such as dendritic arborization.