Abstract: A bacterial filter unit for use in anesthesia applications and respiratory procedures, which bacterial filter unit comprises a two-piece molded housing, each piece being of a generally frusto-conical shape and having an interlocking edge for joining the two housing pieces together in a sealing locking engagement, for retention of a filter media formed of fiberglas or other material between the two housing portions, and for sealing the filter media, each housing portion further having a tubular opening at the peak of the frusto-conical portion for connecting the filter unit in the necessary conduit in the anesthesia or respiratory application apparatus for filtering the bacteria passing through the lines.