Abstract: A breather-sampling-filler assembly (10) for liquid lubrication systems is provided which includes a primary unit (block) (14) adapted for permanent or semi-permanent attachment to a wall (12) of a lubrication system in covering relationship to a lubrication system access opening (13). The unit (14) includes individual breather, fill, and sampling ports (16, 18, 20), and is designed to support a breather (22) in communication with breather port (16), a fill assembly (24) in communication with fill port (18), and a sampling assembly (26) in communication with sampling port (20). The breather (22) includes at least one vent opening (60) and had a selected media (62) therein for desired treatment of solid and liquid airborne contaminants passing into and out of the lubrication system.