We present here three cases of acute otitis media caused by a virulent group A streptococcal infection that rapidly led to deterioration in hearing. Two of the three cases presented with severe sensorineural and mixed hearing loss with multiple tympanic membrane perforations, and the third presented with severe bilateral sensorineural hearing loss following acute otitis media involving group A streptococci. All patients were treated with systemic (piperacillin) and topical antibiotics (ofloxacin ear drops): one patient also received a systemic steroid (betamethasone). Deafness persisted in one patient but in the other two, hearing gradually recovered. Severe cytotoxicity was considered to have occurred in all patients, resulting in multiple perforations of the tympanic membrane and necrosis in the middle ear.