A specimen retrieval device includes a tubular body (410), an inner shaft (418) slidably positioned within a longitudinal bore of the tubular body, and a specimen bag (18) supported on the distal portion of the inner shaft. The specimen bag includes an open end(128), a body, a closed portion (126), and an inner surface (30), the body of the specimen bag including a plurality of folds (132) between the open end and the closed portion, the plurality of folds being movable from a folded state to an unfolded state to increase a volume of the specimen bag. The specimen bag also includes a release string (130) secured to the plurality of folds, the release string movable from a non-actuated position to an actuated position to sequentially release at least one of the plurality of folds from the folded state to the unfolded state to increase the volume of the bag.
