Closed filter holder for microbiological and analytical sampling and testing of gas in pressurized lines. The filter holder consists of a funnel shaped base with a hose nipple, a metal sintered frit as a filter support and a sealing ring, as well as a funnel shaped top part with a hose nipple and a back pressure screen. Thanks to the streamlined design with ideal flow-path geometry, uniform distribution of microorganisms and particles retained is ensured on the filter. The filter holder can be autoclaved or sterilized in a hot air oven.