Background Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by degeneration of anterior horn cells of the spinal cord.The survival motor neuron gene is SMA-determining gene deleted in approximately 95% of SMA patients.This study was undertaken to predict prenatal SMA efficiently and rapidly in families with previously affected child.Methods Prenatal diagnosis was made in 8 fetuses with a family history of SMA.Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used for the detection of the survival motor neuron gene.Results The survival motor neuron gene was not found in 6 fetuses, ruling out the diagnosis of SMA.Two fetuses were detected positive and the pregnancies were terminated.Conclusion Our method is effective and convenient in prenatal diagnosis of SMA.