A yarn cutter for a sewing machine has a movable blade (1) with a yarn entraining region (1b) which can move between a ready position and an entrainment position. It acts with another blade (2), which can move between a ready position and a working position near the needle, to cut the yarn (Y). A front catch (3) holds the blade (2) in the ready position and disengages the movable blade (1) from the blade (2) during the forward motion of the movable blade (1). A rear catch (4) holds the blade (2) in the working position and disengages the movable blade (1) during its rearward motion after cutting the yarn (Y). Also claimed is such an arrangement where the movable blade (1) has a cam region (1c) which releases the blade (2) from the front catch (3) during the forward motion and a second cam region (1d) to release the blade (2) from the rear catch (4) during the rearward motion after cutting the yarn (Y).
