The word consanguineous means of common blood “and characterized by sharing of common ancestors. When blood relatives marry each other, there is an increased risk in the offspring of traits, controlled by recessive genes and those determined by polygenes. Therefore lowering consanguineous marriage would be advantageous to the health of the community. Consanguineous marriage is common where individuals prefer to marry within their clan. consanguineous unions range from cousin-cousin to more distant relatedness and their prevalence varies by culture. Consanguinity has been known to increase the chance of the husband and wife carrying an identical gender derived from a common ancestor. Children of such marriage therefore are at great risk of being homozygous or harmful gene and consequently suffer autosomal recessive genetic disorder. Consanguineous marriages are marriages contracted between blood relatives. According to world health organization guidelines, a consanguineous, marriage is defined as a marriage between people who are second cousins, ore more closely related.7 Aim of the study: The present study aimed to assess the effectiveness of structure teaching programme on knowledge regarding ill effects of consanguineous marriages among adolescents. Methods and material: The research design selected for the present study was one group pretest post test pre-experimental design. The tool used was a self-structured knowledge questionnaire. 100 adolescents were selected using random sampling technique for the study. Study was conducted at various schools of Amritsar, Punjab. Result: The study findings revealed that According to pre test (69%) adolescents had poor knowledge, (31%) had average knowledge and none of them had good knowledge. Whereas according to post test (54%) adolescents had good knowledge and (46%) had average knowledge and none of them had poor knowledge. On comparison post-test mean value 15.96 i.e. higher than pre-test mean value i.e. 7.25. The mean difference between pre test and post test knowledge scores were calculated by t-test and was found to be statistically significant at p<0.05. Conclusion: The results shows that majority of subjects had poor knowledge regarding ill effects of consanguineous marriages in pre-test but after giving Structured Teaching Programme majority of the subjects had a good knowledge. with age, gender, religion, area of living, family income, source of information knowledge found to be non significant at p<0.05 on the other hand there is association of knowledge regarding ill effects of consanguineous marriages among adolescents with type of family, education of parents