Consanguineous marriages are more common in south India primarily because of social and cultural factors. Possibility of a child of consanguineous married couple, suffering from genetic diseases, congenital deformities and auto recessive disorder is more than offspring of non-consanguineous married couple. Consanguineous marriages are more prevalent in rural area because of lack of awareness about consequences. Hence the aim of the study was to educate adolescents regarding consanguineous marriage and its consequences and also to assess their knowledge before and after the intervention. Interventional cross-sectional study was conducted using self-administered questionnaires to assess the knowledge before and after the intervention. Complete enumeration of the students studying in selected schools was done. Lecture method was used with power point presentation to educate the children. Immediate post-test and after two months of intervention follow up test was conducted to assess the retained knowledge. Total 121 students participated in the study. Initially the students had no knowledge about consanguineous marriage and its effect on pregnancy outcome. Increase in knowledge was found to significant immediately after intervention (P=0). After two months of intervention significance was found with increase in the knowledge regarding effects of consanguineous marriage on women’s health (P<0.05). Before intervention only 8.3% and 14% of students knew about association between consanguineous marriage and certain disorders and deafness, after intervention it increased to 90.9%, 91.7% respectively. Retention of knowledge regarding association between consanguineous marriage and congenital heart disease, sickle cell anaemia, haemophilia and genetic disorder was observed. Knowledge regarding consanguineous marriage and its effect on pregnancy outcome was poor among the school students. Structured teaching program about consanguineous marriage and its consequences increased the student’s knowledge.