Objective:To study the laboratory characteristics of adenovirus infected children in Guangzhou in 2004.Methods: 124 children with adenovirus infection hospitalized in Pediatrics Department in our hospital between July and December 2004,were divided into pneumonia group and non-pneumonia group.The white blood cell counts(WBC),percentage of neutrophils(NEU),C-reactive protein(CRP) and erythrocyte sedimentation rate(ESR) were compared between the two groups.Results: The result showed that WBC,NEU,CRP and ESR levels were increased in most of the adenovirus infected children.The WBC,NEU,CRP and ESR were elevated in 67.4%,78.4%,71.1% and 85.7% of the non-pneumonia patients,while in 31.3%,37.5%,56.3%,and 92.8% of the pneumonia group.The WBC and NEU were obviously higher in the non-pneumonia group than the pneumonia group(P0.05).There was no significant difference in CRP and ESR between two groups(P0.05).Conclusion: Findings of our study showed that adenovirus infection caused increased CRP and ESR in the children.WBC and NEU increased significantly in non-pneumonia group of adenovirus infection,but not in pneumonia group.