Background: It is estimated that about 3,000 pregnancies in Iran are at risk for b-thalassemia each year. Objective: To evaluate the diagnostic accuracy of combination of ARMS/PCR and RFLP/PCR techniques in prenatal diagnosis of b-thalassemia.Methods: Sixty-seven b-thalassemia carrier families were enrolled in this study. To analyze b-globin gene, amplification refractory mutation system (ARMS) and restriction fragment length polymorphism (RFLP) methods were used. In order to obtain fetal cells for DNA analysis, chorionic villous sampling (CVS) was implemented.Results: Using the two techniques (i.e. ARMS and RFLP), prenatal diagnosis (PND) was successfully performed in 98.6% of subjects. From 72 cases, 20 fetuses (27.8%) were found to be affected, 32 (44.4%) were heterozygous carriers and 19 (26.4%) were homozygous normal. In 62 families (including 5 twins) the ARMS technique enabled us to trace the mutation in either one or both parents, out of which 46 were further confirmed by RFLP. However, in 16 cases RFLP could not be informative and the diagnosis was based only on ARMS results. In the remaining 10 families, diagnosis was possible only with RFLP.Conclusion: ARMS coupled with RFLP provides an effective way for prenatal diagnosis of b-thalassemia. Using the two techniques together increases the accuracy of PND and in cases in which ARMS is not sufficient to reach a final conclusion, it can be replaced with RFLP. In addition, using these two methods in parallel increases accuracy, saves time and increases confidence.