Hand,foot and mouth disease(HFMD) is one of the most common infectious diseases in young children,especially those under 5 years old.Enterovirus 71(EV71) and coxsackievirus A 16(CA16) are the two major causative organisms of HFMD.In order to understand the etiological agent of HFMD in children in Beijing,throat swabs and/or vesicle fluids were collected from children diagnosed clinically as HFMD from March to October each year during 2007 to 2011.Semi-nested PCR using special primers of 5UTR and VP1 region of CA16and EV71 to identify the types of virus,virus isolation and sequence analysis of VP1 gene were performed.The children were aged from 1 month to 15 years old,and,93.6% of them were younger than 5 years old.Cell culture and reverse-transcription polymerase chain reactions were performed for virus isolation and identification.