In this article the results of the investigation of 391 patients (519 ears) aged 1 month to 15 years with an acute purulent otitis media (APOM) being under treatment in the ENT-department of the Morozov Children's Municipal Clinical Hospital are given. The etiological spectrum of pathogens of acute otitis media was defined. The sample for microbiological investigation was middle ear discharge taken by paracentesis (myringotomy) or fresh spontaneous perforation of the eardrum. Among etiologically decoded APOM 23.6 % were caused by Streptococcus pneumoniae. Repeated and/or recurrent APOM was identified in 52 % of investigated patients. It was concluded that a large number of APOM (46 %) with non-confirmed bacterial etiology require further study and the search for the causative agent of the disease.