Objectives: To find the association between consanguinity and frequency of b-thalassemia and to assess the knowledge of parents regarding disease as well as inclination towards premarital carrier screening  (PMCS), pre natal diagnosis, pre conception genetic counseling. Study Design: A retrospective cohort study. Setting: Patients with beta thalassemia attending Fatimid Foundation and PNS Shifa Hospital, Karachi. Period: Six Months July – December, 2017. Materials and Methods: Data was collected by pre tested questionnaire which include basic demographic profile, frequency of consanguineous marriages and knowledge regarding disease from parents of children suffering from thalassemia. The study was approved by ethical review committee. Data was analyzed using SPSS version 21. Chi square test was applied. Results: Data was collected from 200 study participants including parents of thalassemia. Males were 52% and 48% were the females. 78.5% were relatives (p=0.001) out of these related, first degree relatives were 61% and 17.5% were distant relatives (p 0.009). Only 25% were aware of genetic counseling, 65% know that thalassemia had genetic mode of transmission (p=0.005), 24% were aware of screening modalities available for thalassemic patients (p=0.001). About 63.55% agreed that premarital screening can prevent thalassemia (p=0.001), majority (83%) of parents were not aware of pre natal diagnosis of thalassemia (p=0.001) more than half of study participants (52%) were still in favor of cousin marriages in future. Conclusion: Thalassemia was found most prevalent among first degree familial relatives. Parents have inadequate knowledge regarding disease. Lack of knowledge and trends consanguineous marriages are strong contributory factor for causation of disease.