Abstract: A back pressure filling valve for bottles comprises a central ventilation tube slidably mounted within a valve body member with clearance therebetween to provide an auxiliary passage for the air or gas. A frusto-conical check valve of elastomeric material controls this passage. A liquid control valve is mounted between an outer cylindrical body member and the valve body member and comprises a diaphragm of elastomeric material mounted on the outer cylindrical body member and having a central opening engaging the valve body member.