The auditory function of 75 children affected by homozygous beta0-thalassemia, managed with a low transfusion scheme and treated irregularly with low doses of desferrioxamine, and of 75 controls were examined. In 12 patients a mild bilateral conductive hearing impairment due to bony hypertrophy and/or adenoid hypertrophy was found. In 43 cases a moderate monolateral or bilateral sensory-neural hearing loss at high frequencies with recruitment phenomenon was observed. Ferritin levels were determined in a randomly chosen group of these patients with (14) and without heaing loss (11). In the subjects with sensory-neural hearing loss the mean ferritin levels were significantly higher than in those with no hearing defect. There was no obvious relation between sensory-neural damage on the one hand and Hb levels and unit of blood transfused on the other. The results of this study suggest that iron overload could be a cause of damage in the high frequency elements of the auditory mechanism. Intermittent hypoxia and slow 8th nerve compression due to bony hypertrophy as causes of auditory involvement are also discussed.