Abstract: A cylindrical hammer drill bit with a central fluid passage and having a first group of circumferentially spaced lowermost cutting surfaces located on lowermost arcuate segments spaced by elongated upwardly extending circumferentially spaced slots and a second group of circumferentially spaced uppermost cutting surfaces located in intermediate arcuate segments at the upper end of the slots. Each of the cutting surfaces has an arcuate segment portion on the outer periphery of the drill bit formed at the intersection of upwardly inwardly sloping surfaces with the periphery of the drill bit; and radially inwardly upwardly inclined radial segment portions located on radially rib portions on the upwardly inwardly sloping surfaces. Each radial rib portion is connected to an elongated inwardly facing fluid slot.