PURPOSE: To evaluate the auditory pathways of children with early-treated phenylketonuria through audiometry, immitance tests, and suppression of transient otoacoustic emissions. METHODS: Prospective cross-sectional study with sample composed by 28 children: 12 with phenylketonuria and 16 without the disease. Participants underwent auditory evaluations composed of air- and bone-conduction pure-tone audiometry, speech audiometry, immittance tests and suppression of transient otoacoustic emissions. RESULTS: All participants presented normal results in pure-tone and speech audiometry; however, speech discrimination scores were lower on the phenylketonuria group. Immitance tests revealed normal tympanograms for all children, but stapedial reflex thresholds demonstrated higher thresholds in 2 and 4 kHz for children with phenylketonuria. The suppresion of transient otoacoustic emissions did not show difference in the comparison between groups. CONCLUSION: The basic audiologic assessment do not identify hearing disorders in children with phenylketonuria; however, speech discrimination scores were lower and stapedial reflexes were higher in these children, which may indicate auditory processing disorders. The study of the suppression of transient otoacoustic emissions demonstrated integrity of the olivocochlear efferent system in children with phenylketonuria.