Abstract: A filter particularly for infusion and transfusion apparatus, comprises a housing having an inlet passage and a discharge passage spaced from the inlet passage. The housing includes a surface with a spiral flow passage defined thereon which is centrally communicated to the discharge passage. A filtering material is placed over the spiral in the housing which is made up of two parts which are interconnectable at the location of the spiral and which also act to hold the filter material in position. In an alternate embodiment, the housing of the filter is formed as a portion of a cannula. The inlet and outlet flow passages of the housing may be arranged to align axially, for example, on one side of the housing, or they may be offset.