Tumor samples from 236 gastric carcinoma patients and throat washings (TWs) from 135 healthy adults were collected and screened for EBV genome. 17 Epstein-Barr virus associated gastric carcinoma (EBVaGC) and 33 EBV positive TWs were further examined for type 1/2 EBV and polymorphism at Bam HI F, Bam HI W1/I1 boundary regions and Xho I restriction site in LMP1 gene. No type f of Bam HI F polymorphism was found in all the cases, nor type 2 in EBVaGC. 25 of 33 TWs (75.8%) analyzed detected type 1 virus, while 8 TWs (24.2%) detected type 2 virus. Type I and i of Bam HI W1/I1 polymorphism accounted for 1(5.9%) and 16 (94.1%) in EBVaGC and 11 (33.3%) and 19 (57.6%) in TWs, respectively. LMP1 Xho I(+) and (-) polymorphism accounted for 0(0) and 15 (88.2%) in EBVaGCs and 12 (36.4%) and 18 (54.5%) in TWs, respectively. Among those specimens with determinable genotypes through all the polymorphism, the distribution rate of type 1/i/Xho I(-) in EBVaGC (15/15, 100%) was significantly higher than that in TWs (4/28, 14.3%) (chi2 = 29.098, P < 0.0001), suggesting that the distinctive EBV strain (1/i/Xho I(-)) could be associated with Chinese EBVaGC.