A polymeric surgical ligating clip is provided having curved leg members joined by a resilient hinge. A leg member includes a flexible rib protruding from a vessel clamping inner surface and extends longitudinally between the proximal and distal end portions of the leg member. The flexible rib defines a channel extending transversely through the rib along a majority of said length. The flexible rib can collapse and provides better retention of the clip on a vessel. The clip can contain a flexible rib on both legs in an interlocking fashion. Or a plurality of teeth can protrude from a second vessel clamping inner surface of a second leg member. The plurality of teeth can include first and second rows of teeth extending longitudinally on the second leg member, transversely separated from each other on opposite sides of a centerline of the clip.
