Abstract For the pathological evaluation of the chorioamniotic membranes, a membrane roll is made to give an orientation to the sections and to cover more extended planes. We designed a new instrument, Annie's memb-roller, for easy preparation of membrane rolls. Annie's memb-roller has two non-toothed arms which are 2 mm wide, 1 mm thick, and 8 cm long. To test its effectiveness in making a membrane roll, the placentas obtained from pregnant women (n = 10) with various obstetrical conditions were used. Preparation of the membrane rolls using Annie's memb-roller was easy and successful in all cases tested. The lengths of the membranes measured from fresh placentas and paraffin sections showed a very good correlation (p < 0.001; r = 0.941). Application of the memb-roller would be very helpful in the semi-quantitative analysis of the chorioamniotic membranes and the standardization of placental pathology and research practice.