Abstract: An improved mousetrap has an upper jaw pivotally mounted with a lower jaw, and a bait platform mounted between the upper and lower jaws, The bait platform acts as a trigger to initiate jaw closure when depressed. A circumferential spring for closing the jaws around the bait platform encircles the jaws and is retained in a retaining groove of the lower jaw. The upper jaw has a rear, lower corner for retaining the spring when the jaws are open; and a rear, upper corner for retaining the spring when the jaws are closed. Contractile force of the spring pulls the spring from the lower corner toward the upper corner, to complete jaw closure.