This invention relates to a blood filter assembly in which blood enters at the bottom end of the assembly, is directed in spirally upward path and then passes through a filter medium. After passing through the filter medium, the blood flows downwardly out of an outlet in the bottom end of the assembly. A gas vent is provided at the top end of the assembly. In its preferred embodiment, the outer shell of the assembly tapers from the bottom end to a narrower diameter top end, the filter medium is generally shaped in the form of a cylindrical tube and a core member is provided radially inwardly of said filter medium and spaced therefrom. This filter assembly is particularly useful for the removal of particulate matter, gas and other foreign materials from blood.