Unilateral cochlear hearing loss is considered as a risk factor for auditory, verbal-communicative, behavioral and academic development. An early diagnosis is therefore necessary.182 consecutive patients with an age up to 10 years were diagnosed with permanent hearing loss in the mild to profound range in a defined 5-years-period (1.10.1994-30.9.1999) in the Pedaudiologic Outpatient Clinic of the University Göttingen. Fifty children (27.5%) had a unilateral hearing loss (30 sensorineural, 20 conductive caused by aural atresia with or without microtia), 132 a bilateral one. This paper presents the data of the consecutive series of the 30 sensorineural unilaterally hearing-impaired children (> 25 dB).A slight male predominance was present (53.3%). The left ear was affected in 43.3%, the right ear in 56.7%. In the majority of the cases the hearing loss was severe and profound. The hearing-impairments were diagnosed by the median age of 69.5 months and all aided by the median age of 70 months. The etiology remained unknown in 60 per cent of the cases. Hearing aid acceptance at the first follow-up (on average after 6 months) was found to be 79 per cent.The data suggest the relevance and necessity of a pedaudiometric prevention. They demonstrate the urgent necessity of a molecular genetic cause investigation. Recessive sensorineural hearing loss with onset in infancy may exist with no antecedent family history.