Acute Respiratory Infections (ARIs) are classified according to the compromised anatomical site. The etiology can be associated with viruses, bacteria and fungi. The etiological agents that are responsible for the highest incidence in children, around 50 to 90% of occurrences, are viruses. This study aims to characterize the factors that contribute to acute respiratory infection in children from 0-6 years old and the main symptoms that are presented, thus classifying the etiological agents. This is a descriptive quantitative study carried out by the molecular virology laboratory of the Research Center in Tropical Medicine-CEPEM/RO and the Oswaldo Cruz Foundation Rondonia-FIOCRUZ/RO. Data collection was performed through a questionnaire with 660 patients of both sexes, with questions about socioeconomic data and clinical manifestations, from February to December 2013. Prevalent clinical manifestations were cough, coryza, pulmonary secretion, fever, nasal obstruction, otalgia, adventitious sounds, apnea, dyspnoea and ocular pruritus of the 113 children diagnosed with acute respiratory infection, the highest incidence was in males. The proposed pathogens in the study were rhinovirus, parainfluenza 1, 2, 3, and adenovirus. Parainfluenza 2 and rhinovirus are the most prevalent.