This invention relates broadly to surgical instruments. More particularly, this invention relates to a surgical snare instrument for excising polyps. Preferably, the instrument includes a coupling member that may increase ability to actuate the snare. According to a preferred embodiment, the present invention comprises a surgical instrument for insertion through an endoscope having a handle and a working channel, said surgical instrument including an elongate flexible tubular sheath having proximal and distal ends; a flexible shaft extending through and axially movable relative to the sheath, said shaft having proximal and distal ends; an end effector coupled to or formed at said distal end of said shaft; and a coupling member disposed at said distal end of said shaft.