Decidualization of the endometrial stroma is an essential feature of the implantation stage of pregnancy. It denotes the transformation of endometrial stromal fibroblasts into specialized secretory decidual cells that provide a nutritive and immunoprivileged matrix essential for embryo implantation and placental development. progesterone induce secretory differentiation in endometrial glands and decidual–type change in the stroma . In the absence of a progestational  stimulus , a decidual reaction in a postmenopausal women is very uncommon and encountered as an incidental finding . Common causes of postmenopausal bleeding includes endometrial atrophy, endometrial  hyperplasia, endometrial carcinoma, In our case there is no evident exogenous and endogenous source of progesterone  . After excluding all the causes of bleeding in postmenopausal,  this report presents a case of idiopathic decidual change in an postmenopausal women which itself is the cause of bleeding. Diagnosis was achieved by histopathology  and ultrasonography.  we are presenting this case with the aim that  decidual change in postmenopausal can be idiopathic and associated with bleeding  with relevant review of literature.