A serological mass survey was carried out in Wuzhou City of the Guangxi Autonomous Region, China. Sera were collected from 12,932 persons between the ages of 40 and 59. The positive rate of VCA/IgA antibody-positive persons was 5.3%, but no EA/IgA antibody was found in sera from VCA/IgA-negative persons. Thirteen and nine nasopharyngeal carcinoma (NPC) patients were detected from the VCA/IgA and EA/IgA antibody-positive persons, respectively. With the present combination method the detection rate of NPC for 12,932 persons was 100.5/100,000 and for 680 VCA/IgA antibody-positive persons it was 1,900/100,000. Thus, the rate was twice and 37 times higher, respectively, than the annual incidence rate of NPC in persons of the same age group from 1975-1978 in Wuzhou City. Of 13 NPC patients, 9 were in stage 1(70%) and 4 in stage II (30%). Therefore, it is possible to reduce the mortality rate of NPC in Wuzhou City by radiotherapy of NPC patients in the early stage of the disease. The present results further suggest that EB virus is closely associated with NPC.