A survey of the prevalence of smoking in middle school students aged 13-21 years in Harbin city, China, was undertaken in the Spring of 1988. A random sample of 4712 students was selected using proportional stratified clustering. A self-administered confidential questionnaire relating to smoking habits and certain family and school factors was administered. The results showed that 1.29% of the students (2.21% boys and 0.38% girls) smoked regularly, 5.62% (10.52% boys and 0.76% girls) were light smokers and 13.77% (24.29% boys and 2.92% girls) smoked only occasionally. Smoking habits were related to the type of school and to age, there being a higher proportion of smoking in senior grade students. Students were significantly more likely to smoke if they were male and if their siblings smoked. Prevalence of regular smoking was not related to parental occupation or family income. It is suggested that anti-smoking education in the school curriculum should be directed towards students in middle school.