The present study investigated the messenger RNA (mRNA) expression of myostatin and myostatin receptors (activin receptor-like kinase 4 [ALK4], transforming growth factor (TGF)-β type I receptor kinase [ALK5] and activin receptor type IIB [ActRIIB]) in endometrium of healthy women during menstrual cycle as well as in benign (endometriosis, polyps) and malignant (endometrial adenocarcinoma) conditions.