The incidence of induced abortion (IA) is high in Vietnam. The purpose of this study is to find out whether IA increases the risk of secondary tubal infertility. A case-control study was conducted at Tu Du Hospital in Vietnam between June and September 2001. Interviews were completed with 67 tubal infertility cases matched by age and residence to 67 controls. The median age of subjects was 34 years old. Proportion of subjects with history of IA was 50.8% and 44.8% for cases and controls, respectively. IA did not significantly increase the risk of secondary infertility. Age of first sexual intercourse was under 20 years old for 29.9% of cases and 9.1% of controls, and it significantly increased the risk of secondary infertility [odds ratio (OR)=3.80]. This study was unable to identify IA as a risk factor of secondary tubal infertility. However, the increased OR for age at first sexual intercourse may imply that being sexually active at an earlier age increases the risk of getting both sexually transmitted diseases and unwanted pregnancies and in turn, increasing the risk of infertility. It is recommended to provide young women and men with the information about health risks related to sexual activity.