Abstract: Esophageal balloon eytology sereening was performed in 1995, in Songkhla where has the highest rate of esophageal cancer in Thailand, to identify precancer-our lesions and risk faetors of esophageal cancer.This was the first to make diagno-of balloon eytology by chinese eytologic criteria abroad.The results of the 559 subjects show the same three features in the smears as that in chinese high incidence area Linxian:high incidence of abnormal cells; high frequeney of hyperkeratosis and lots of fungi and inflammatory cells. It is demonstrated again that in regions where the rate of cancer is high, the incidence of dysplasia is also high; and sug-gested the presence of fungal contamination and vitamin deficieney. Additionally, smoking, alcohol drinking, betel chewing, tobacco chewing were also found to be related to higher risk of having abnormal cells by cytology sereening together with interviewing.