The expression and distribution of the imprinted paternally expressed gene 10 (PEG10) in decidual tissues of 36 patients with inevitable abortion and 36 normal pregnant (NP) women were examined by RT-PCR, immunohistochemistry, in situ hybridization and Western blot. Decidual PEG10 mRNA expression was significantly lower in the patients than that in the NP group by RT-PCR (P<0.05). The characteristic PEG10 expression was confirmed by in situ hybridization. As shown by Western blot and immunohistochemistry, PEG10 protein expression was consistent with the mRNA expression pattern. The results showed that maintaining sufficient levels of PEG10 may be important during early pregnancy. Lower levels of PEG10 might be one of reasons that underlie inevitable abortion.