Objective To understand the status of infection and epidemic trend of Dengue fever and Chikungunya in Guangdong.Methods Retrospective survey and literature review were used to obtain data on the incidence,etiology of Dengue and Chikungunya.Serological survey was conducted to detect the specific-antibodies in healthy individuals for both Dengue virus (DENV) and Chikungunya virus (CHIKV).Results Three epidemics of Dengue fever were observed during 1990-2012,with the annual incidence rates as 9.75/100 000 in 1995,1.76/100 000 in 2002 and 1.25/100 000 in 2006,respectively.The predominant epidemic strains appeared to be DENV-2 and DENV-4 during 1990-1994.Since 1995,DENV-1 had become the predominant transmission strain which lasted for almost 13 years.Co-existence of multiple serotypes of DENV started in 2009.Of the 7 718 sera from healthy population during 2003-2012,180 specimens were detected positive for specific DENV-IgG antibody,ended with a sero-prevalence rate of 2.33％.All 2 132 sera in 2012 were detected negative for CHIKV-IgG antibody.Conclusion The overall exposure level to Dengue was considered to be low in Guangdong province.However,the predominant transmission mode caused by DENV-1 had been gradually changed into the co-existence of multiple serotypes with the endemic signs appeared in some part of the areas.Chikungunya was a newly emerging disease in Guangdong since local people were lack of basic immunity barrier.Surveillance and control programs thus seemed important.