Objective: The present study aims at characterizing the functional status of the central nervous system (CNS) in encoding speech sounds in large-for-gestational-age (LGA) neonates as examined through a sensitive auditory evoked potential termed frequency-following response (FFR). Design: Case-control study. Setting: SJD Barcelona Children’s Hospital (Catalonia, Spain). Population: A sample of 25 LGA neonates were paired by age and sex with 25 born adequate-for-gestational-age (AGA). Methods: Descriptive statistics were calculated for sociodemographic characteristics of the mother and their neonates. Categorical demographic and electrophysiological variables were analyzed by Chi-square test and continuous variables with t test or Mann-Whitney U test. Main Outcome Measures: The primary clinical outcomes were the FFR spectral amplitude and its normalization. Both magnitudes reflect the neural encoding strength of the fundamental frequency of the eliciting stimulus. Results: LGA neonates displayed smaller spectral amplitudes compared to the AGA group (consonant transition: P = .002; vowel: P = .004) as well as smaller normalized spectral amplitudes (consonant transition: P = .01; vowel: P = .003). Conclusions: This study reveals for the first time perinatal CNS consequences of being born LGA, characterized by a deficient neural encoding of speech sounds. Funding: This work was supported by the Spanish Ministry of Science and Universities PGC2018-094765-B-I00 project and the MDM-2017-0729-18-2 Maria de Maeztu Center of Excellence, the 2017SGR-974 Excellence Research Group of the Generalitat de Catalunya, and the ICREA Acadèmia Distinguished Professorship awarded to Carles Escera. Keywords: auditory brainstem response, auditory evoked potentials, BMI, EEG, FFR, macrosomia, newborn, neonatal adiposity, universal hearing screening.