Abstract: A bit retainer for impact type pneumatic tools arranged to be mounted on the tool and to releasably receive a bit. The retainer includes a body having a bore extending therethrough. The bore includes a nose portion of generally elliptical configuration, a center portion of circular configuration and a rear portion of generally elliptical configuration that has its major axis disposed at about 90.degree. relative to the major axis of the front portion of the bore. Radially movable locking members are provided that operate in cooperation with a movable sleeve. The sleeve is movable between unlatched and latched positions which permit and prevent radial movement of the locking members to positively retain the bit unless the sleeve is intentionally moved to the unlatched position.