Background and aims We analysed the significance of the alimentation factor as one of otitis media (OM) risk factors in children of the first year of life. Methods Two groups of children were included in the Project. First group consisted with 452 children of the first year of life with OM, the second group presented 258 practically healthy children. Children from the first group had OM with silent course in the majority of cases. Diagnostics was based on anamnesis, pneumatic otoscopy, impedance audiometry and surgical findings. Analysed factors were quality of formula (breast milk or modern formula) and position in time of feeding (horizontal and semi-vertical), night feeding, and presence of regurgitation. Results Horizontal position and night feeding had strong correlation with presence of OM. Impedance audiometry in dynamics and analysis of electro-acoustic compliance demonstrated some pathogenic features of OM in infants in dependence of feeding position. OM treatment was more effective when included preventive measurers of middle ear reflux. Conclusion Development of OM in infants depended on position of the child in time of feeding, night alimentation and presence of regurgitation. The analysis of the electroacoustic compliance is the most sensitive in diagnostics of OM in infants and reflects even minimal changes in middle ear cleft related to a horizontal position during feeding. Treatment of OM in infants has to include changes of child position.