Abstract: An aseptic sampler fitting including a conduit portion for in-line connection between two pipes containing a viscous fluid, a neck portion associated with the conduit portion defining an access opening therein providing access to the interior of the conduit portion, and a cover being securable to the neck portion for covering the access opening defined therein utilizes a gasket positionable between the neck portion and the cover for maintaining a complete physical separation between the cover and the neck portion. The components of the fitting are smoothly-surfaced to facilitate cleaning of the fitting, and the cover includes a plurality of pierceable, self-closing elastomeric stoppers permitting the insertion through the cover of a hypodermic needle or the like for the purpose of extracting a sample of fluid contained within the conduit portion. The cover is constructed of components facilitating ease of replacement of the elastomeric stoppers.