We used real-time reverse transcription-polymerase chain reaction (QRT-PCR) to detect wild-type ERalpha and ERbeta and their isoforms as well as exon 5 splicing variant mRNA ERalpha in various types of endometrial hyperplasia in perimenopausal women. Our data suggest that the exon 2 and 7 deletion ERalpha mRNA isoforms are present in endometrial tissue undergoing various hyperplastic states. Wild type ERbeta mRNA and their isoforms 2, 4, 5, 6 were observed in each type of assessed endometrial specimens, and ERalpha/delta5 was found only in hyperplasia complex group.