BackgroundWhile ear anomalies and hearing impairment are common in patients with craniofacial microsomia (CFM), their prevalence, characteristics, and relationship to speech-language development remain unclear. PurposeThis study analyzed the prevalence and risk factors for hearing impairment in patients with CFM. Study Design, Setting, SampleThis retrospective cohort study included patients with unilateral or bilateral CFM from a single center between January 1980 and July 2023 who had evidence of a hearing assessment at <18 years. Exclusion criteria were inconclusive CFM diagnosis by clinical examination and/or radiographs or incomplete medical records. Predictor VariablesThe predictor variables included presence or absence of cleft lip and/or palate, laterality of CFM, and external ear and mandibular anomaly scores measured using the Orbit, Mandible, Ear, Nerve, and Soft Tissue (OMENS) and Pruzansky-Kaban classifications. Main Outcome VariablesPrimary outcome variable was hearing impairment, measured through air and bone conduction audiometry and categorized by type, severity, and side. Secondary outcome variable was speech-language delay, evaluated through assessments of expressive and receptive language skills, vocabulary, speech intelligibility, general articulation, and phonological speech. CovariatesThe covariates included sex and age at first hearing assessment. AnalysesLogistic regression models were used to analyze the effect of predictors on outcomes. P-value <0.05 was considered significant. ResultsThe sample included 213 patients (61.5% male). Hearing assessments were performed at a mean age of 4.6 ± 4.8 years. Hearing impairment was found in 183 (85.9%) and was predominantly conductive (n=130, 91.5%). Of subjects with hearing impairment, 158 (86.3%) had external ear anomalies (P<0.001). In patients with unilateral CFM, 38 (21.8%) had bilateral hearing loss and 9 (5.2%) had contralateral-only hearing loss. Both M3 and E3 scores were associated with the presence and severity of hearing loss (P=0.01 and P<0.001, respectively). There was no significant association between hearing impairment and speech-language development (P>0.05). Conclusion and RelevanceAlthough the severity of mandibular and external ear anomalies was significantly associated with the prevalence and severity of hearing loss, clinicians should remain alert for concomitant or isolated contralateral hearing loss, given the high prevalence of hearing loss in ears without ipsilateral facial involvement or external abnormalities.