Viruses are frequent causes of upper respiratory tract infections in children. We investigated the viral aetiology of community-acquired upper respiratory tract infections (URIs) in young children treated as outpatients in community settings. During November 2008, nasal swab specimens were taken from children with recent onset of upper respiratory tract infections. The patients attended day care or primary schools; the specimens were randomly obtained by pediatricians from schools and childcare institutions and sent for identification by PCR method. A total of 300 specimens were collected. From all samples, 40.67% were positive for at least 1 virus, viz. adenovirus 11.76%, rhinovirus 9.8%, respiratory syncytial virus 6.08%, influenza virus 5.56%, parainfluenza virus 4.9%, enterovirus 2.94% and a combination of 2 viruses 2%. Clinical manifestations of the respiratory infections were as follows: 70.7% of the patients had coryza, 69.3% cough, 26% sneezing, 19.7% sore throat, 2.7% headache, 7.7% fever, 2.3% conjunctivitis, 1.3% abdominal pain and 1% hoarseness. The results of this study demonstrate that adenoviruses and rhinoviruses are the two most common viral agents isolated from pediatric outpatients with acute URIs in autumn in Arak City. Coryza and cough were the most common symptoms in children. Sore throat and hoarseness were more prevalent in infections caused by influenza virus, conjunctivitis in parainfluenza, and coryza in rhinovirus infections.