Retrospective analysis of own experiences and investigations concerning the role of the viral etiology in acute gastroenteritis were presented. Stools of children and soldiers with acute gastroenteritis were examined by electron microscopy. The most frequent causative agents were rotaviruses and much less frequently found were other viral particles of: coronaviruses, adenoviruses, Norwalk-like viruses, astroviruses, caliciviruses and "small round viruses".