Background Hand,foot and mouth disease (HFMD) is an emerging public health problem in China,not only threatening the health of children,but also causing tremendous loss and burden to both families and society.The aim of this study was to characterize the epidemiology and clinical features of HFMD,and to understand the key factors affecting HFMD in the Harbin region to provide scientific evidence for effective prevention and control strategies.Methods Epidemiological and clinical information from 2379 randomly chosen cases of HFMD treated at the Harbin Center for Disease Control and Prevention from May 2008 to November 2011 were analyzed.All cases were separated into common and severe HFMD,with key factors for severe HFMD analyzed using multivariable Logistic regression.Results Among the 2379 patients,1798 were common cases and 581 severe cases,14 of which resulted in death.Most cases were in children younger than 5 years.Morbidity peaked in July and was higher in the surrounding country and cities than in Harbin proper.Medical expenses were significantly higher for severe than for common cases (P <0.001).The primary clinical symptoms were fever and erythema; laboratory examination showed leucocytosis together with pneumonia,carditis,and abnormal electrocardiogram and electroencephalogram in severe cases.Multivariable Logistic regression analysis showed that the key factors for severe HFMD were age,morbidity location,morbidity area,fever duration,mouth mucosal symptoms,and abnormal serum levels of neutrophils (NEUT),hemoglobin and glucose (P <0.05).Conclusions To improve prognosis,reduce medical expense and prevent the development of severe cases,we should improve the epidemiological detection of HFMD to treat patients quickly.We should also closely monitor children with the EV71 virus,who present with continuous fever as well as abnormal laboratory results,from areas highly susceptible to HFMD attacks.