Abstract: Objective To investigate the epidemiological features of human calicivirus( HuCV) infection in children with diarrhea in a hospital in Guangzhou. Methods Stool specimens were collected from children with viral diarrhea diagnosed between October, 2003 and January, 2004 and between October, 2004 and January, 2005. HuCV was detected by means of RT-PCR and sequence analysis of the PCR products. Results Eighty specimens positive for Norwalk-like viruses (NLVs) were identified from 648 stool specimens, with a positivity rate of 12.35%, and sapporo-like viruses (SLVs) were identified in 2 specimens (0.31%). The monthly NLV positivity rate was 11.74% (Oct.), 14.16% (Nov.), 9. 09% (Dec.) and 13.95% (Jan.), respectively, showing no significant variation in these months. NLVs mainly infected children below 2 years old. Twenty-two strains of NLVs were sequenced and analyzed, and 21 of them were identified as GⅡ and the genotype of 1 strain could not be determined. The prevalent viral population were GⅡ-3 and GⅡ-4 in 2003 and was GⅡ-4 in 2004, and both of the SLVs belong to GⅠ-1. Conclusion NLVs is one of the important pathogens causing sporadic acute gastroenteritis in children admitted in the hospital in Guangzhou, and the prevalent strains are GⅡ-3 and GⅡ-4 , but different prevalent strains are possible in different periods.