A marker delivery device is configured for deploying a tissue marker. Themarker delivery device includes a handlehaving a chamber, and a cannula. According to one aspect, the cannula has aflexible portion formed by a slot arrangementhaving of a plurality of spaced-apart substantially parallel peripheral slotsextending through the side wall of the cannula to the lumen.A marker introducer rod is movably disposed in the lumen of the cannula fordeploying the mark, and has a flexible regionthat corresponds to the flexible portion of the cannula. According to anotheraspect, a retraction mechanism is mounted to the handleand is configured to facilitate a complete retraction of both the cannula andthe marker introducer rod into the chamber of thehousing of the handle upon an actuation of the retraction mechanism.