Abstract: Objective To investigate Noroviruses (NVs) infection among children under 5 years of age with nonbacterial diarrhea.Methods NVs were detected by amplification of cDNA from the viral RNA by RT-PCR using priner pair JV13I/JV12Y.Amplicons obtained from NVs-positive stools were purified and sequenced Sequences were compared with prototye sequences retrieved from NCBI database.Results 957 fecal specie ens were collected.For 469 rotavirus-negative specieens,NVs positive rate was 23.88%(112/469).All 35 sequenced strains belonged to NLV CII in which 28 strains were CII-4,6 strains were CII-3 and 1 strain could not be d identified.Conclusion NVs with different genotypes circulated among children in Guangzhou,and CII-4 were the prevalent strain.