Abstract: Objective This study was designed to gain insight into the changes in the incidences and risk factors of chronic diseases among residents in Zhejiang Province．Methods Some 20,000 residents in 12 counties and districts in Zhejiang Province were selected in 1998 and 2003 using a stratified，multistage cluster sampling method for household survey based on the uniform question．Naire for health service investigations designed by the Ministry of health of P．R．China．Results The incidence of chronic diseases in cities and rural areas was 6.37％ and 25.29％ respectively higher in 2003 than in 1998，with a higher amplitude in the incidence increase in rural areas than in cities．The incidence of hypertension was ranked as the first of all the chronic diseases．There was an dramatic increase in the incidence of hypertension，diabetes mellitus and cardiac diseases．The incidence of cigarette smoking increased by 25.33％ with a more dramatic increase in the inci-dence in the rural areas than in the cities．The survey revealed that there was an increase by 33％ in the number of heavy smokers．The alcohol-drinking rate among residents decreased from 20.43％ in 1998 t0 17.97％ in 2003．The rate of physical exercise among residents in cities and rural areas were roughly the same in the 2 surveys. Conclusion With population aging and the increase in the rate and amount of cigarette smoking，the chronic diseases among residents in the cities and rural areas of Zhejiang Province take on an increasing tendency，and further efforts need to be strengthened to intervene with and control the risk factors such as smoking．