Abstract: Objective To study the relationship of genetic characteristics and incidence risk of nasopharyngeal cancer(NPC).Methods The familial members of new NPC cases and their spouse in Sihui,Guangdong were interviewed.The content of interview included environmental factors,dietary intake,smoking,occupation and disease history.Results The results of complex segregation by regressive logistic model showed that the NPC risk was related with senrior brother's or sister's state besides relating with parent's state.After excluding the effect of family and smoking,the genetic character istics of NPC susceptibility fit a mendelian tr ansmission model.Conclusion It suggested that familial clustering of NPC was likely to be a product of genetic constitution and environmental exposures.There may be a major gene which decided the susceptibility to NPC.