BACKGROUND: Thalassemia is considered as the most common single gene disorder worldwide. Preventive measures include identification of thalassemia carriers (traits) through screening, genetic counselling and prenatal diagnosis to reduce the incidence. This study aims at estimating the prevalence of carrier status detection among the extended family members of children having thalassemia major so as to use it as a screening prevention strategy with appropriate counselling.METHODS: This cross-sectional study was conducted in thalassemia unit of Pediatric Department of a tertiary care teaching hospital over a period of 18 months. Blood samples were collected from 117 extended family members (EFM) of 23 children with thalassemia major to carry out investigations such as Complete Blood Counts (CBC), Naked Eye Single Tube Red Cell Osmotic Fragility Test (NESTROFT), Reticulocyte count, High Performance Liquid Chromatography(HPLC) and serum ferritin. Reports were analysed to find out the prevalence of carriers.RESULTS: Among 117 EFM, 62 (52.9%) were males while 55(47.1%) were females. Mean age distribution in this study was 16.49 years (8.5). Prevalence of thalassemia trait (carrier) was 35%. NESTROFT test was positive in 57(48.7%) participants. The binary logistic regression found only positive NESTROFT test as a predictor (adjusted OR=0.022, P=0.001) of having raised HbA2 (HbA2≥3.5 %).CONCLUSION: Screening of thalassemia carrier by targeting extended family members of thalassemia major children could yield more carrier cases and targeted counselling could help effectively in decreasing the number of children born with thalassemia major. This strategy could be included in future plan of national prevention programme for thalassemia.KEYWORDS: Thalassemia carrier, HPLC, NESTROFT, Extended Family Members