The present invention provides a flexible respirator filter having substantially coextensive front and back portions of filter material which are sealed to each other along their periphery, forming a sealed edge. A flexible plastic frame is contained within the front and back portions to form a plenum between the front and back portions of filter material. The frame has a peripheral edge which remains adjacent to the sealed edge of the filter material along substantially the entire length of the sealed edge to provide sufficient rigidity to prevent crushing while at the same time providing sufficient flexibility to fit under other personal protective equipment. A connector for attaching the filter to the respirator mask is formed integrally with the frame such that it protrudes through the back portion of the filter material. A plurality of recesses are also formed integrally with the frame to facilitate grasping the filter without crushing or damaging it.