As many as 15% of human cancers are caused by infections of viruses. Among these seven cancer viruses, two closely related human gammaherpesviruses Kaposi sarcoma herpesvirus (KSHV or HHV8) and Epstein-Barr virus (EBV) cause several important cancers in China. KSHV is causally associated with Kaposi’s sarcoma, which is common in Xinjiang, China while EBV is linked to nasopharyngeal carcinoma and 20% of gastric cancer, which are common in Southern China. Works from our laboratory have provided critical insights into the molecular mechanisms of KSHV infection and KSHV-induced oncogenesis, and identified numerous promising therapeutic targets and agents for KSHV infection and KSHV-associated cancers, which have the potential for translating into clinics to benefit the patients. Similar strategy can be applied to EBV and its associated cancers, which will be discussed for ongoing studies of nasopharyngeal carcinoma and gastric cancer in Shantou University Medical College. The urgent needs to develop KSHV and EBV vaccines for preventive and therapeutic applications will also be discussed during the symposium.