Abstract: In accordance with illustrative embodiments of the present invention as disclosed herein, a breath sample collecting device includes a flexible plastic bag having a mouthpiece and inlet valve assembly connected adjacent one end of the bag, and a sample transfer assembly connected adjacent the other end of the bag. The transfer assembly has a sleeve attached to a neck on the bag, such sleeve having an inner end wall which mounts a hollow needle having a sharp tip on its outer end in a manner such that the tip is within the bore of the sleeve to prevent accidental stick injuries. A rubber boot which closes the tip, and an elastomer stopper on an associated transfer device, are selectively pierced by the needle tip in response to compressive force to permit transfer of a breath sample from the bag to such associated device.