Abstract: An aseptic valve construction including a valve body having an inlet flow passage and at least one outlet flow passage. The valve body has a valve seat surrounding the inlet flow passage and has an opening therein in alignment with the inlet flow passage and in communication with the inlet flow passage and with the at least one outlet flow passage. A shoulder providing a shoulder seat surrounding the opening is provided in the valve body. A diaphragm is disposed in the valve body and has a surface adapted to be moved into engagement with the valve seat and another surface in engagement with the shoulder seat. The diaphragm has a cylindrical portion extending between the surface engaging the valve seat and the surface engaging the shoulder seat. The cylindrical portion has a length and a constant inner diameter and a constant outer diameter along its length for preventing the cylindrical portion from buckling or wrinkling.