Background: Major β-thalassemia occurs when impaired genes received by a neonate from the parents. In most of the parents, there are no apparent clinical manifestation and they just show some impairments in hematological indices. This study was designed to determine prevalence of minor and silent carries parents that have children suffering from major β-thalassemia, compare it with national protocol about prevention of thalassemia. Methods: A blood sample was taken from parents of all major thalassemic patients covered by TaleghaniHospitalin Gorgan (n = 195), CBC and Hemoglobin electrophoresis were done. Data were analyzed using SPSS software. Results: Amongst 196 parents one case have normal level of MCV, MCH, RBC, HbA, HbF and mentzer = 22.05 (0.51%) that diagnosed as alpha triplication/N by real time PCR, RFLP informative. The means of hematological indices were based on the national protocol. Conclusion: Present results showed that there are a few cases of thalassemia disorders with normal MCV, MCH, RBC, Mentzer index and Hb electrophoresis which could be missed in routine and pre-marital screening tests, resulted in a thalassemia child that it is possible in every screening test. Generally, indices were according to range of the national guideline.