Abstract: This concrete retaining wall block comprises a flat, elongated base, two side walls upstanding from the longitudinal sides of the base, a front panel upstanding from the base and joining with the side walls; the top edge of each side wall is provided with a series of notches, the notches of both side walls registering in pairs transversely of the block. The front panel forms a transverse ridge downwardly protruding from the base and adapted to engage any selected notch of a subjacent block, whereby the slope of a retaining wall built of such blocks can be varied and yet the blocks are all laid out horizontally, permitting to use a horizontal foundation for the wall.