Retrospective study on the epidemiology of 9 cholera outbreaks at Hai Phong city during 1976-1996 was carried out basing on some epidemiological characteristics of cholera outbreaks allowed providing the hypothesis of cholera at Hai Phong was imported. V.cholera O1 generated the Ogawa serum type in 1976, 1980 and 1981; Inaba serum type in 1983, 1986 and 1987; Ogawa serum type in 1994, 1995 and 1996. The incidence from 22 to 43/100.000 population and it was high in the first outbreaks. The rate of adults was higher (64%-87%) than that in children and old people.